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1. Extreme structural stability of Ti0.5Sn0.5O2 nanoparticles: synergistic effect in the cationic sublattice

Author

Denis Machon, Sylvie Le Floch, Shashank Mishra, Stéphane Daniele, Karine Masenelli-Varlot, Patrick Hermet, Patrice Mélinon, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Transport, Nanomagnétisme et Matériaux pour l'Énergie (ENERGIE), IRCELYON-C'Durable (CDURABLE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), École Supérieure de Chimie Physique Électronique de Lyon (CPE), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Consortium Lyon Saint-Etienne de Microscopie (CLYM), École normale supérieure de Lyon (ENS de Lyon)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), and Université de Montpellier (UM)

Subjects
[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science
Abstract

International audience; Ti0.5Sn0.5O2 nanoparticles (∼5 nm and ∼10 nm) have been studied under high pressure by Raman spectroscopy. For particles with diameter ∼10 nm, a transformation has been observed at 20–25 GPa while for particles with ∼5 nm diameter no phase transition has been observed up to ∼30 GPa. The Ti0.5Sn0.5O2 solid solution shows an extended stability at the nanoscale, both of its cationic and anionic sublattices. This ultrastability originates from the contribution of Ti and Sn mixing: Sn stabilizes the cationic network at high pressure and Ti ensures a coupling between the cationic and anionic sublattices. This result questions a “traditional” crystallographic description based on polyhedra packing and this synergistic effect reported in this work is similar to the case of metamaterials but at the nanoscale.

Published
2022

2. Effect of High Pressure Spark Plasma Sintering on the Densification of a Nb-Doped TiO2 Nanopowder

Author

Shashank Mishra, Nicholas Blanchard, Gilbert Fantozzi, Sandrine Cottrino, Stéphane Daniele, Sylvie Le Floch, Alexandre Verchère, Thomas Gaudisson, Stéphane Pailhès, Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Centre National de la Recherche Scientifique (CNRS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, and Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Anatase, Materials science, Sintering, Spark plasma sintering, 02 engineering and technology, lcsh:Chemical technology, lcsh:Technology, 01 natural sciences, nanopowder TiO 2, Phase (matter), 0103 physical sciences, densification rate, lcsh:TP1-1185, grain growth, Ceramic, Composite material, 010302 applied physics, lcsh:T, General Medicine, 021001 nanoscience & nanotechnology, Microstructure, Grain growth, high-pressure spark plasma sintering, visual_art, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], visual_art.visual_art_medium, nanopowder TiO2, Crystallite, 0210 nano-technology
Abstract

International audience; Sintering under pressure by means of the spark plasma sintering (SPS) technique is a common route to reduce the sintering temperature and to achieve ceramics with a fine-grained microstructure. In this work, high-density bulk TiO 2 was sintered by high pressure SPS. It is shown that by applying high pressure during the SPS process (76 to 400 MPa), densification and phase transition start at lower temperature and are accelerated. Thus, it is possible to dissociate the two densification steps (anatase then rutile) and the transition phase during the sintering cycle. Regardless of the applied pressure, grain growth occurs during the final stage of the sintering process. However, twinning of the grains induced by the phase transition is enhanced under high pressure resulting in a reduction in the crystallite size.

Published
2020

3. A Multitechnique Study of Fluorinated Nanodiamonds for Low-Energy Neutron Physics Applications

Author

Michela Brunelli, Chiara Cavallari, Marc Dubois, Nicolas Batisse, Valery Nesvizhevsky, S. Radescu, Vittoria Pischedda, Michael Herraiz, Institut de Chimie de Clermont-Ferrand (ICCF), SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, European Synchrotron Radiation Facility (ESRF), Dutch-Belgian Beamline DUBBLE at the ESRF, Grenoble, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Universidad de La Laguna [Tenerife - SP] (ULL), Institut de Chimie de Clermont-Ferrand - Clermont Auvergne (ICCF), Sigma CLERMONT (Sigma CLERMONT)-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Materials science, Halogenation, Analytical chemistry, Infrared spectroscopy, 02 engineering and technology, engineering.material, 010402 general chemistry, 01 natural sciences, Nanomaterials, [SPI]Engineering Sciences [physics], symbols.namesake, [CHIM]Chemical Sciences, Neutron, Physical and Theoretical Chemistry, [PHYS]Physics [physics], Granular materials, Scattering, Diamond, Pair distribution function, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Carbon, Nanocrystals, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, General Energy, Amorphous carbon, engineering, symbols, Carbon nanomaterials, 0210 nano-technology, Raman scattering
Abstract

International audience; Data of quasi-specular reflection of cold neutrons, prompt-γ neutron analysis, X-ray Raman scattering (XRS), and neutron pair distribution function (PDF) analysis with powder of detonation nanodiamonds are analyzed to collect their structural properties and chemical composition. Both as-synthesized and purified samples were studied using fluorination samples. Removal of both the sp2 amorphous carbon shell and the hydrogen atoms is evidenced respectively by the change of neutron-nuclei optical potentials of nanoparticles and the increase of their neutron reflectivity. Moreover, sp3 diamond cores of nanoparticles stay intact during the fluorination as revealed by similar scattering patterns, PDF, and XRS data. Quasi-specular reflection, PDF, and XRS data are complementary for the study of nanomaterials and in good agreement with conventional characterization techniques (infrared spectroscopy and solid-state NMR).

Published
2020

4. Strain and Piezo-Doping Mismatch between Graphene Layers

Author

Martin Kalbac, Denis Machon, Alfonso San-Miguel, Félix Balima, Rémy Fulcrand, Alexis Forestier, G.S. Pinheiro, Colin Bousige, Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Luminescence (LUMINESCENCE), Laboratoire des Multimatériaux et Interfaces (LMI), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Departamento de Física, Campus Ministro Petrônio Portella Bloco 03, Universidade Federal do Piauí, Universidade Federal do Piauí, Liquides et interfaces (L&I), J. Heyrovský Institute of Physical Chemistry of the ASCR, Czech Academy of Sciences [Prague] (CAS), Laboratoire Nanotechnologies et Nanosystèmes [Sherbrooke] (LN2), Université de Sherbrooke (UdeS)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Materials science, Nitrogen, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, law.invention, Two dimensional materials, law, Doping, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Physical and Theoretical Chemistry, Electronic properties, [PHYS]Physics [physics], Strain (chemistry), business.industry, Graphene, Bilayer, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, General Energy, Modulation, Alcohols, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Optoelectronics, Layers, 0210 nano-technology, business
Abstract

International audience; Modulation of electronic properties of bilayer materials through the strain and doping mismatch between layers opens new opportunities in 2D material straintronics. We present here a new approach allowing to generate asymmetric strain or doping between layers and a method to quantify it using a supported isotopically labeled bilayer graphene studied by in situ Raman spectroscopy. Strain differences up to ∼0.1% between the two graphene layers have been obtained by applying pressures of up to 10 GPa with nonpolar solid environments. However, when immersed in a liquid polar environment, namely, a mixture of ethanol and methanol, a piezo-doping mismatch between layers is observed. This asymmetrical doping increases with pressure, leading to charge concentration differences between layers of the order of 1013 cm–2. Our approach thus allows disentangling strain and doping effects in high-pressure experiments evidencing the asymmetries of these phenomena and comforting isotopic bilayer graphene as a benchmark system for the study of asymmetric effects in devices or composite surfaces.

Published
2020

5. Microcanonical Nucleation Theory for Anisotropic Materials Validated on Alumina Clusters

Author

Patrice Mélinon, Ken Miyajima, Arsène Chemin, David Amans, Fumitaka Mafuné, Luminescence (LUMINESCENCE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), The University of Tokyo (UTokyo), and (nano)Matériaux pour l'énergie (ENERGIE)

Subjects
[PHYS]Physics [physics], Canonical ensemble, Energy, Nucleation kinetics, Cluster chemistry, Chemistry, Monomers, Nucleation, Thermodynamics, 02 engineering and technology, Metal clusters, 021001 nanoscience & nanotechnology, 01 natural sciences, Gas phase, [SPI]Engineering Sciences [physics], 0103 physical sciences, [CHIM]Chemical Sciences, Desorption, Physical and Theoretical Chemistry, 010306 general physics, 0210 nano-technology, Anisotropy
Abstract

International audience; Nucleation kinetics in gas phase remains an open issue with no general model. The derivation of the reaction constants assuming a canonical ensemble fails to describe anisotropic materials such as oxides. We have developed a general and versatile model using activated complex kinetics with a microcanonical approach. This approach handles the kinetics issue in cluster growth when the transient nature of the processes hinders the use of the canonical ensemble. The model efficiently reproduces experimental size distributions of alumina clusters formed by laser ablation with different buffer gas densities, including magic numbers. We show that the thermodynamic equilibrium is not reached during the growth. The bounding energy measured is 10 times lower than the one deduced from DFT calculation, but also the one expected from the bulk cohesive energy.

Published
2020

6. Optimum in the thermoelectric efficiency of nanostructured Nb-doped TiO2 ceramics: from polarons to Nb–Nb dimers

Author

Alexandre Verchère, Stéphane Daniele, Gilbert Fantozzi, Sylvie Le Floch, Shashank Mishra, Sandrine Cottrino, Shantanu Misra, Régis Debord, Christophe Candolfi, Stéphane Pailhès, Bertrand Lenoir, Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Centre National de la Recherche Scientifique (CNRS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC), IRCELYON-C'Durable (CDURABLE), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, and Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Materials science, Condensed matter physics, General Physics and Astronomy, 02 engineering and technology, 021001 nanoscience & nanotechnology, Polaron, Thermal conduction, 01 natural sciences, [SPI]Engineering Sciences [physics], Thermal conductivity, Lattice constant, Electrical resistivity and conductivity, Rutile, Seebeck coefficient, 0103 physical sciences, Thermoelectric effect, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, 010306 general physics, 0210 nano-technology
Abstract

International audience; Rutile is the most common and stable polymorph form of titanium oxide TiO2 at all temperatures. The doping of rutile TiO2 with a small amount of niobium is reknown for being responsible for a large increase of the electrical conductivity by several orders of magnitude, broadening its technological interest towards new emerging fields such as the thermoelectric conversion of waste heat. The electronic conduction has been found to be of a polaronic nature with strongly localized charges around the Ti3+ centers while, on the other side, the relatively high value of the thermal conductivity implies the existence of lattice heat carriers, i.e. phonons, with large mean free paths which makes the nanostructuration relevant for optimizing the thermoelectric efficiency. Here, the use of a high-pressure and high-temperature sintering technique has allowed to vary the grain size in rutile TiO2 pellets from 300 to 170 nm, leading to a significant reduction of the lattice thermal conductivity. The thermoelectric properties (electrical conductivity, Seebeck coefficient and thermal conductivity) of Nb-doped rutile nanostructured ceramics, namely NbxTi1−xO2 with x varying from 1 to 5%, are reported from room temperature to ∼900 K. With the incorporation of Nb, an optimum in the thermoelectric properties together with an anomaly on the tetragonal lattice constant c are observed for a concentration of ∼2.85%, which might be the fingerprint of the formation of short Nb dimers.

Published
2020

7. Raman spectroscopy to determine CO2 solubility in mafic silicate melts at high pressure: Haplobasaltic, haploandesitic and approach of basaltic compositions

Author

Nicolas Sator, Julien Amalberti, Philippe Sarda, Daniel R. Neuville, Charles Le Losq, Bertrand Guillot, Tahar Hammouda, Sylvie Le Floch, Eva Chamorro-Pérez, Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique de la Matière Condensée (LPTMC), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
0106 biological sciences, Basalt, Andesite, Partial melting, Mineralogy, Geology, 010502 geochemistry & geophysics, Early Earth, 010603 evolutionary biology, 01 natural sciences, Silicate, chemistry.chemical_compound, CO2 content, chemistry, 13. Climate action, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], Carbonatite, Mafic, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

CO2 degassing of mafic silicate melts is an important part of the terrestrial carbon cycle, at mid-ocean ridges, oceanic hot spots, or in the middle of continents. Deeper CO2-bearing mafic magmas may also exist, such as those suspected in the D″ zone, and certainly existed in the magma ocean of the early Earth. Knowledge of the CO2 solubility in mafic melts at high pressure is therefore important but unknown at present. Results from molecular dynamics simulation (e.g., Guillot and Sator, 2011) predict that CO2 solubility in basalt may be much higher than previously thought at pressures and temperatures relevant to the upper mantle. But some recent models predict low solubility at high pressure (e.g., Eguchi and Dasgupta, 2018). The present study thus experimentally investigates the solubility of CO2 in basalt and andesite in the pressure range 1.5–8.5 GPa at 1820–2130 K in oxidizing conditions. Up to 4 GPa, the quenched samples are essentially vitreous and CO2-saturated. Their CO2 contents are measured using confocal micro-Raman spectroscopy, where we establish an internal calibration line relating CO2 content to the area of the Raman band assigned to the ν1 stretching vibration of carbonate groups. This calibration appears independent from the spectrometer, sample or experimentalist, thus enhancing confidence in this method. At 5 and 8.5 GPa, some of the quenched samples are found partially crystallized. Their CO2 abundance is estimated at micro-scale from Raman mapping, and at large scale from image analysis and presence/absence of vesicles. Over the 1.5–8.5 GPa pressure range, obtained CO2 concentrations vary between 1.8 and > 13.6 wt%. At 5 GPa and 1873 K, the CO2 content in basalt and andesite are similar. These findings experimentally confirm the ability of mafic melts to accommodate large amounts of CO2 at conditions prevailing in the deep Earth. A consequence is that magmas issued from partial melting of carbonate-bearing silicate rocks may ascend with significant quantities of CO2 of several wt% and more: when reaching shallower depths, they may degas large quantities of CO2. Present estimates of the global carbon flux to the atmosphere may thus be underestimated, and implications to early magma ocean degassing may be considered. Other consequences may concern the genesis of kimberlites and carbonatites. We finally speculate that, if silicate melts exist in the D″ zone, significant amounts of carbon may be stored there, and consequences may arise as to carbon sequestration in the core.

Published
2021

8. Vitreous Carbon, Geometry and Topology: A Hollistic Approach

Author

Patrice Mélinon, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Surface (mathematics), vitreous carbon, Computer science, General Chemical Engineering, Hyperbolic geometry, Structure (category theory), 02 engineering and technology, Review, 010402 general chemistry, Topology, 01 natural sciences, [SPI]Engineering Sciences [physics], Robustness (computer science), [CHIM]Chemical Sciences, General Materials Science, QD1-999, Topology (chemistry), Geometry and topology, [PHYS]Physics [physics], Minimal surface, Isotropy, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Chemistry, thin films, 0210 nano-technology, applied topology
Abstract

Glass-like carbon (GLC) is a complex structure with astonishing properties: isotropic sp2 structure, low density and chemical robustness. Despite the expanded efforts to understand the structure, it remains little known. We review the different models and a physical route (pulsed laser deposition) based on a well controlled annealing of the native 2D/3D amorphous films. The many models all have compromises: neither all bad nor entirely satisfactory. Properties are understood in a single framework given by topological and geometrical properties. To do this, we present the basic tools of topology and geometry at a ground level for 2D surface, graphene being the best candidate to do this. With this in mind, special attention is paid to the hyperbolic geometry giving birth to triply periodic minimal surfaces. Such surfaces are the basic tools to understand the GLC network architecture. Using two theorems (the classification and the uniformisation), most of the GLC properties can be tackled at least at a heuristic level. All the properties presented can be extended to 2D materials. It is hoped that some researchers may find it useful for their experiments.

Published
2021

9. Isostructural phase transition by point defect reorganization in the binary type-I clathrate Ba7.5Si45

Author

Holger Euchner, Vittoria Pischedda, Denis Machon, Alfonso San-Miguel, Patrice Mélinon, Stéphane Pailhès, Michael Hanfland, Régis Debord, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Helmholtz Institute Ulm (HIU), European Synchrotron Radiation Facility (ESRF), Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Laboratoire Nanotechnologies et Nanosystèmes [Sherbrooke] (LN2), Université de Sherbrooke (UdeS)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke] (3IT), Université de Sherbrooke (UdeS), and Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)

Subjects
010302 applied physics, Diffraction, Phase transition, Isostructural phase transitions, Materials science, Polymers and Plastics, Metals and Alloys, Ab initio, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Crystallographic defect, Landau theory, Electronic, Optical and Magnetic Materials, Condensed Matter::Materials Science, Chemical physics, Vacancy defect, 0103 physical sciences, Ceramics and Composites, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Structural complexity, Isostructural, 0210 nano-technology, Single crystal
Abstract

International audience; Competition between microscopic point defect (vacancy and interstitial) configurations is inherent to crystalline phases of increased structural complexity. Phase transitions that preserve symmetry between them belong to a specific class of isostructural transitions. Type-I silicon clathrates are representatives of such structurally complex crystalline phases showing an intriguing structural transition at high pressure associated with an abrupt reduction of volume with no indication for any breakage of symmetry. Using isothermal high-pressure X-ray diffraction performed on a single crystal of the simplest representative type-I silicon clathrates, binary Ba 8 Si 46 , we confirm the isostructural character of the transition and identify the associated mechanism. A detailed analysis of the atomic structural parameters across the transition in combination with ab initio studies allow us to pinpoint a microscopic mechanism driven by a rearrangement of point defects initially present in the structure. An analysis based on the Landau theory gives a coherent description of the experimental observations. A discussion on the analogy between this transformation and liquid-liquid transitions is proposed.

Published
2021

10. Probing the coupling between the components in a graphene-mesoporous germanium nanocomposite using high-pressure Raman spectroscopy

Author

Richard Arès, Stéphanie Sauze, Abderraouf Boucherif, Denis Machon, Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke] (3IT), Université de Sherbrooke (UdeS), Laboratoire Nanotechnologies et Nanosystèmes [Sherbrooke] (LN2), Université de Sherbrooke (UdeS)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, chemistry.chemical_element, Bioengineering, Germanium, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, law.invention, symbols.namesake, [SPI]Engineering Sciences [physics], law, [CHIM]Chemical Sciences, General Materials Science, Coupling, [PHYS]Physics [physics], Nanocomposite, Graphene, General Engineering, General Chemistry, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, chemistry, High pressure, symbols, 0210 nano-technology, Mesoporous material, Material properties, Raman spectroscopy
Abstract

International audience; The nature of the interface between the components of a nanocomposite is a major determining factor in the resulting properties. Using a graphene-mesoporous germanium nanocomposite with a core-shell structure as a template for complex graphene-based nanocomposites, an approach to quantify the interactions between the graphene coating and the component materials is proposed. By monitoring the pressure-induced shift of the Raman G-peak, the degree of coupling between the components, a parameter that is critical in determining the properties of a nanocomposite, can be evaluated. In addition, pressure-induced transformations are a way to tune the physical and chemical properties of materials, and this method provides an opportunity for the controlled design of nanocomposites.

Published
2021

11. Nanoscale Coal Deformation and Alteration of Porosity and Pore Orientation Under Uniaxial Compression: An In Situ SANS Study

Author

Rui Zhang, Shimin Liu, Alfonso San-Miguel, Ralf Schweins, Sylvie Le Floch, Vittoria Pischedda, Pennsylvania State University (Penn State), Penn State System, Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, (nano)Matériaux pour l'énergie (ENERGIE), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
[PHYS]Physics [physics], Materials science, Macropore, Bedding, business.industry, 0211 other engineering and technologies, Geology, 02 engineering and technology, Neutron scattering, 010502 geochemistry & geophysics, Geotechnical Engineering and Engineering Geology, 01 natural sciences, Stress (mechanics), Nanopore, [SPI]Engineering Sciences [physics], [CHIM]Chemical Sciences, Coal, Deformation (engineering), Composite material, Porosity, business, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Civil and Structural Engineering
Abstract

International audience; Nanoscale coal deformation affects thegeomechanics response of coal structure under external stress conditions. In this study, insitu small-angle neutron scattering (SANS) is used to characterize the evolution of nanopore structures under uni-axial compression on an Illinois coal specimen. Porod invariant mapping is used to estimate apparent porosities at different azimuthal angles. Structure-free orientation factors, including the alignment factor and Hermans’ orientation factor, are used to characterize orientation degree in nanopores quantitatively. The nanoscale pore deformation and evolution with stress have not been directly measured before, and the insitu SANS technique offers the unique capability to probe the nanoscale rock deformation. From the results, higher values of apparent porosities are shown near the coal bedding direction.At dif-ferent azimuthal angles, the apparent porosities increase with increasing uniaxial stress in the elastic deformation range (54–575bar) for the measured coal. The pore-scale degree of orientation is a size-dependent parameter, and pore orientation along the coal bedding generally increases as pore size increases. The degree of orientation in nanopores on average (in a size range between ~ 2 × 103Å and ~ 15Å) tends to increase first and then decreases with increasing stress loading, although different from that of macropores, indicating higher stresses on the nanopore edges along the bedding direction and then on the nanopore body along the normal direction. There is no distinct permanent change ofporosity within the measured stress range (0–575 bar)after the stress relief

Published
2021

12. Giant Tuning of Electronic and Thermoelectric Properties by Epitaxial Strain in p-Type Sr-Doped LaCrO3 Transparent Thin Films

Author

Ignasi Fina, Geneviève Grenet, Stéphane Pailhès, D. Han, Romain Bachelet, Claude Botella, Régis Debord, Marc d'Esperonnat, R. Moalla, Valentina M. Giordano, Guillaume Saint-Girons, European Commission, Agence Nationale de la Recherche (France), Centre National de la Recherche Scientifique (France), Université de Lyon, Ministerio de Ciencia e Innovación (España), Generalitat de Catalunya, INL - Matériaux Fonctionnels et Nanostructures (INL - MFN), Institut des Nanotechnologies de Lyon (INL), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-École Centrale de Lyon (ECL), Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE), Institut de Ciència de Materials de Barcelona (ICMAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Orders of magnitude (temperature), FOS: Physical sciences, 02 engineering and technology, (La1-xSrx)CrO3 solid solution, Applied Physics (physics.app-ph), 01 natural sciences, 7. Clean energy, Condensed Matter - Strongly Correlated Electrons, Electrical resistivity and conductivity, Seebeck coefficient, 0103 physical sciences, Thermoelectric effect, Ultimate tensile strength, Materials Chemistry, Electrochemistry, Thin film, Composite material, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, 010306 general physics, Perovskite (structure), Transparent conducting film, Condensed Matter - Materials Science, Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Physics - Applied Physics, 021001 nanoscience & nanotechnology, Electronic, Optical and Magnetic Materials, Electronic transport, P-type transparent conductors, Thermoelectric properties, Epitaxial films, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Strain effect, 0210 nano-technology
Abstract

The impact of epitaxial strain on the structural, electronic, and thermoelectric properties of p-type transparent Sr-doped LaCrO3 thin films has been investigated. For this purpose, high-quality fully-strained La0.75Sr0.25CrO3 (LSCO) epitaxial thin films were grown by molecular beam epitaxy on three different (pseudo)cubic (001)-oriented perovskite-oxide substrates: LaAlO3, (LaAlO3)0.3(Sr2AlTaO6)0.7, and DyScO3. The lattice mismatch between the LSCO films and the substrates induces in-plane strain ranging from -2.06% (compressive) to +1.75% (tensile). The electric conductivity can be controlled over two orders of magnitude, σ ranging from ~0.5 S cm-1 (tensile strain) to 35 S cm-1 (compressive strain). Consistently, the Seebeck coefficient S can be finely tuned by a factor of almost two from ~127 μV K-1 (compressive strain) to 208 μV K-1 (tensile strain). Interestingly, we show that the thermoelectric power factor (PF = S2 σ) can consequently be tuned by almost two orders of magnitude. The compressive strain yields a remarkable enhancement by a factor of three for 2% compressive strain with respect to almost relaxed films. These results demonstrate that epitaxial strain is a powerful lever to control the electric properties of LSCO and enhance its thermoelectric properties, which is of high interest for various devices and key applications such as thermal energy harvesters, coolers, transparent conductors, photo-catalyzers and spintronic memories., Financial support from the European Commission through the project TIPS (H2020-ICT-02-2014-1-644453), the French national research agency (ANR) through the projects MITO (ANR-17-CE05-0018), LILIT (ANR-16-CE24-0022), DIAMWAFEL (ANR-15-CE08-0034-02), the CNRS through the MITI interdisciplinary programs (project NOTE), IDEX Lyon-St-Etienne through the project IPPON, the Spanish Ministerio de Ciencia e Innovación, through the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV2015-0496) and the MAT2017-85232-R (AEI/FEDER, EU), PID2019-107727RB-I00 (AEI/FEDER, EU), and from Generalitat de Catalunya (2017 SGR 1377) is acknowledged. The China Scholarship Council (CSC) is acknowledged for the grant of Dong Han. Ignasi Fina acknowledges Ramón y Cajal contract RYC-2017-22531. Seebeck measurements at ILM were made within the ILMTech transport platform. The authors are also grateful to Jean-Baptiste Goure, Philippe Regreny, Aziz Benamrouche, and Bernat Bozzo for their technical support and the reviewers for their valuable and constructive comments that have improved the quality of the manuscript.

Published
2021
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13. Impact of temperature and mode polarization on the acoustic phonon range in complex crystalline phases: A case study on intermetallic clathrates

Author

Turner, S., Pailhès, S., Bourdarot, F., Ollivier, J., Raymond, S., Keller, T., Sidis, Y., Castellan, J.-P., Lory, P.-F., Euchner, H., Baitinger, M., Grin, Yu., Schober, H., De Boissieu, M., Giordano, V., Institut Laue-Langevin (ILL), Science et Ingénierie des Matériaux et Procédés (SIMaP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Magnétisme et Diffusion Neutronique (MDN ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Max-Planck-Institut für Festkörperforschung, Max-Planck-Gesellschaft, Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut für Festkörperphysik, Helmholtz Institute Ulm (HIU), Max-Planck-Institut für Chemische Physik fester Stoffe (CPfS), ILL, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay

Subjects
Condensed Matter::Materials Science, Physics, ddc:530, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]
Abstract

The low and weakly temperature-varying lattice thermal conductivity, κL (T), in crystals with a complex unit cell such as type-I clathrates is assumed to originate from a reduced momentum and energy space available for propagative lattice vibrations, which is caused by the occurrence of low-energy optical phonon modes. In the context of ab initio self-consistent phonon (SCP) theory, it has been shown that the cubic and quartic anharmonic interactions result in a temperature-induced energy renormalization of these low-lying optical branches which contributes to the anomalous behavior of κL (T) in structurally ordered type-I clathrates [T. Tadano and S. Tsuneyuki, Phys. Rev. Lett. 120, 105901 (2018)]. By means of inelastic neutron scattering, we provide evidence for this energy renormalization in temperature, which has been resolved for transversely and longitudinally polarized phonons in the single crystal type-I clathrate Ba7.81Ge40.67Au5.33. By mapping the neutron intensity in the momentum space, we demonstrate the coherent character of the low-lying optical phonons. The overall phonon spectrum and dynamical structure factors are satisfactorily reproduced by ab initio harmonic calculations using density functional theory with the meta-GGA SCAN functional and a fully ordered structure. However, a polarization-dependent cutoff energy with opposing temperature shifts for longitudinal and transverse acoustic dispersions is experimentally observed which is not reproduced by the simulations. Anharmonicity affects the energies of the low-lying optical phonons in the transverse polarization, which compares quantitatively well with available results from SCP theory, whereas differences are observed for the longitudinal polarization

Published
2021
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14. Role of a fractal shape of the inclusions on acoustic attenuation in a nanocomposite

Author

Wang Haifeng, Anthony Gravouil, Anne Tanguy, Yue Ren, Qing Zhou, Valentina M. Giordano, Haoming Luo, Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne] (LaMCoS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), State Key Laboratory of Solidification Processing, Northwestern Polytechnical University [Xi'an] (NPU), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), and ANR-20-CE05-0046,MAPS,Approche multi-echelle pour une comprehension microscopique du transport thermique dans les nanocomposites(2020)

Subjects
Length scale, Materials science, QC1-999, Phonon scattering, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, Nanocomposites, [SPI.MAT]Engineering Sciences [physics]/Materials, Dendrite (crystal), Fractal, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Wave mechanics, General Materials Science, Acoustic attenuation, 010306 general physics, Thermal transport, [SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], Condensed matter physics, Condensed Matter - Mesoscale and Nanoscale Physics, Physics, Attenuation, General Engineering, Acoustic wave, 021001 nanoscience & nanotechnology, Wavelength, Phononic crystal, Thermal conductivity, Glass, 0210 nano-technology, TP248.13-248.65, Elastic modulus, Biotechnology, Acoustic signal processing
Abstract

Nanophononic materials are promising to control the transport of sound in the GHz range and heat in the THz range. Here we are interested in the influence of a dendritic shape of inclusion on acoustic attenuation. We investigate a Finite Element numerical simulation of the transient propagation of an acoustic wave-packet in 2D nanophononic materials with circular or dendritic inclusions periodically distributed in matrix. By measuring the penetration length, diffusivity, and instantaneous wave velocity, we find that the multi-branching tree-like form of dendrites provides a continuous source of phonon-interface scattering leading to an increasing acoustic attenuation. When the wavelength is far less than the inter-inclusion distance, we report a strong attenuation process in the dendritic case which can be fitted by a compressed exponential function with $\beta>1$., Comment: 14 pages, 11 figures

Published
2021

15. Stability and Lattice Dynamics of Ruddlesden–Popper Tetragonal Sr 2 TiO 4

Author

B. Fraisse, Patrick Hermet, Romain Viennois, Denis Machon, David Maurin, Alexander Paul Petrović, Michael Marek Koza, David Bourgogne, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire Nanotechnologies et Nanosystèmes [Sherbrooke] (LN2), Université de Sherbrooke (UdeS)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke] (3IT), Université de Sherbrooke (UdeS), Institut Laue-Langevin (ILL), ILL, Department of Quantum Matter Physics [Geneva] (DQMP), University of Geneva [Switzerland], Laboratoire Charles Coulomb (L2C), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Bulk modulus, Materials science, Condensed matter physics, Anharmonicity, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Heat capacity, Thermal expansion, Inelastic neutron scattering, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Tetragonal crystal system, symbols.namesake, General Energy, symbols, Physical and Theoretical Chemistry, Perturbation theory, 0210 nano-technology, Raman scattering
Abstract

International audience; We report a combined experimental and theoretical lattice dynamics study of the Ruddlesden–Popper layered compound Sr2TiO4. From inelastic neutron scattering experiments, we derive the generalized phonon density of states of Sr2TiO4. We also report its heat capacity, thermal expansion, and thermodynamic Grüneisen parameters using the calculated bulk modulus and find a large value of about 2. Using Raman scattering experiments under pressure, we discuss a potential structural distortion of the tetragonal structure above 11 GPa, which could be due to nonhydrostatic compression. The mode Grüneisen parameters of the four Raman-active modes are determined and shown to be in reasonable agreement with those obtained by density functional perturbation theory (DFPT) calculations. The temperature behavior of the Raman-active modes was studied, allowing us to determine the implicit volume and explicit anharmonic contributions. Above 400 K, the implicit volume contribution dominates the temperature-induced variation of the four Raman-active modes, whereas, below this temperature, the explicit anharmonic contribution is the dominant contributor to the highest energy mode. Our results underline the importance of anharmonicity in vibration-related properties of Sr2TiO4.

Published
2020

16. Tuning C–F Bonding of Graphite Fluoride by Applying High Pressure: Experimental and Theoretical Study

Author

Nicolas Batisse, S. Radescu, H. Diaf, Chiara Cavallari, Marc Dubois, Vittoria Pischedda, European Synchroton Radiation Facility [Grenoble] (ESRF), Departamento de Física Fundamental II, MALTA Consolider Team, and Instituto de Materiales y Nanotecnología, Universidad de La Laguna, Departamento de Física Fundamental II, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de Clermont-Ferrand (ICCF), SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), ANR-16-IDEX-0001,CAP 20-25,CAP 20-25(2016), ESRF- The European Synchrotron Radiation Facility, Grenoble, European Synchrotron Radiation Facility (ESRF), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Imagination, Anions, Materials science, Chemical substance, phase transformation, media_common.quotation_subject, Analytical chemistry, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, DFT, law.invention, Anode materials, chemistry.chemical_compound, symbols.namesake, Magazine, Chemical structure, law, Graphite, Physical and Theoretical Chemistry, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Graphite fluoride, media_common, X-ray Raman scattering, Energy, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Carbon, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, high pressure, General Energy, chemistry, High pressure, symbols, 0210 nano-technology, Science, technology and society, Fluoride, Raman scattering
Abstract

International audience; C 2 F graphite fluoride has a unique mutable structure when subjected to external applied pressure. In the present study, we examine C 2 F using X-ray Raman scattering (XRS) up to 6.5 GPa coupled with theoretical simulations. Using the XRS technique, we follow the in situ high pressure evolution of the energy loss corresponding to the C and F K-edge. Significant variations occur at 2.9 GPa, remain up to 6.5 GPa and persist at ambient conditions after decompression. The permanent changes are related to an increased planarity of the graphitic layers and a modulation of the fluorine configuration. The all-electron density of a C 2 F-sp 3 slab obtained from the DFT simulation and the Quantum Theory of Atoms in Molecules (QTAIM), reveals the appearance of bond-critical points between in-plane and out of plane F-F, suggesting an increasingly ionic character of the structure under biaxial isotropic strain. Pressure can be used as an alternative to chemical synthesis for tuning C-F bonding and metastabilizing new intercalated fluorine compounds with potentially improved electrochemical properties.

Published
2020

17. Sound velocity and refractive index of pure N2 fluid and of equimolar N2 –CO2 fluid mixture up to 15 GPa

Author

Agnès Dewaele, Valentina M. Giordano, P. Loubeyre, Frédéric Datchi, S. Ninet, Gunnar Weck, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Mixing (process engineering), Analytical chemistry, Physics::Optics, General Physics and Astronomy, Frequency shift, 02 engineering and technology, 01 natural sciences, Diamond anvil cell, 0103 physical sciences, Diamond anvil cells, Acoustical properties, Thermodynamic states and processes, Physical and Theoretical Chemistry, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, Adiabatic process, Sound velocity measurement, Optical properties, Light scattering, 021001 nanoscience & nanotechnology, Brillouin zone, Interferometry, Equations of fluid dynamics, Brillouin spectroscopy, 0210 nano-technology, Joule heating, Refractive index
Abstract

International audience; The sound velocity and refractive index of pure N2 and of the equimolar N2–CO2 mixture are measured up to 15 GPa and 700 K in a resistive heating diamond anvil cell. The refractive index vs pressure is obtained by an interferometric method. The adiabatic sound velocity is then determined from the measurement of the Brillouin frequency shift in the backscattering geometry and the refractive index data. No phase separation of the N2–CO2 fluid mixture is observed. The fluid mixture properties are discussed in terms of ideal mixing.

Published
2020

18. Spectral fluctuation in SERS spectra of benzodiazepin molecules: The case of oxazepam

Author

Katharina Gratzer, Trang N. T. Phan, Cédric Pardanaud, David Bergé-Lefranc, Denis Machon, Alexis Forestier, Stéphane Coussan, Virginie Hornebecq, Alexandre Merlen, Institut des Matériaux, de Microélectronique et des Nanosciences de Provence (IM2NP), Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire Nanotechnologies et Nanosystèmes [Sherbrooke] (LN2), Université de Sherbrooke (UdeS)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke] (3IT), Université de Sherbrooke (UdeS), Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Matériaux divisés, interfaces, réactivité, électrochimie (MADIREL), ANR-16-CE09-0021,DOMTOM,Design de matériaux sur mesure nanoporeux et multifonctionnels : vers la détection de médicaments par le couplage des propriétés d'adsorption et de la réponse Raman(2016), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Aix Marseille Université (AMU), and Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UMR237-Aix Marseille Université (AMU)-Avignon Université (AU)

Subjects
Materials science, Analytical chemistry, 02 engineering and technology, 01 natural sciences, Spectral line, Drug detection, symbols.namesake, Molecule, General Materials Science, Physics::Chemical Physics, ComputingMilieux_MISCELLANEOUS, Spectroscopy, [PHYS]Physics [physics], 010401 analytical chemistry, Surface-enhanced Raman spectroscopy, 021001 nanoscience & nanotechnology, 3. Good health, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Colloidal gold, symbols, Density functional theory, Absorption (chemistry), 0210 nano-technology, Raman spectroscopy
Abstract

International audience; The surface‐enhanced Raman spectroscopy (SERS) spectra of a benzodiazepine molecule, oxazepam, have been recorded using a nanoporous silica matrix containing gold nanoparticles as SERS substrate. In the measured spectra, we clearly observe spectral fluctuations, with slight shifts in wavenumber, appearance, and disappearance of peaks and variations in the shape of some peaks. By comparison with spectra simulated by density functional theory, we attribute those fluctuations to the experimental signature of various adsorption sites of the molecule on the gold surface. The effect of temperature and laser power was also studied, suggesting that changes in absorption sites can be optically activated. Such features could cause misinterpretation of SERS spectra and errors in the identification of drugs. We suggest that they should be systematically considered for the correct interpretation of SERS spectra of drug molecules.

Published
2020

19. Continuum constitutive laws to describe acoustic attenuation in glasses

Author

Haoming Luo, Anne Tanguy, Valentina M. Giordano, Anthony Gravouil, Walter Schirmacher, Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne] (LaMCoS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut für Physik [Mainz], Johannes Gutenberg - Universität Mainz (JGU), ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Physics, [PHYS]Physics [physics], Phonon, Scattering, Attenuation, Glasses, Metamaterial, Mechanics, 01 natural sciences, Viscoelasticity, 010305 fluids & plasmas, Mechanical & acoustical properties, Amorphous materials, [SPI]Engineering Sciences [physics], Macroscopic scale, 0103 physical sciences, Dissipative system, [CHIM]Chemical Sciences, Acoustic phonons, 010306 general physics, Acoustic modeling, Acoustic attenuation
Abstract

International audience; Nowadays metamaterials are at the focus of an intense research as promising for thermal and acoustic engineering. However, the computational cost associated to the large system size required for correctly simulating them imposes the use of finite-elements simulations, developing continuum models, able to grasp the physics at play without entering in the atomistic details. Still, a correct description should be able to reproduce not only the extrinsic scattering sources on waves propagation, as introduced by the metamaterial microstructure, but also the intrinsic wave attenuation of the material itself. This becomes dramatically important when the metamaterial is made out of a glass, which is intrinsically highly dissipative and with a wave attenuation strongly dependent on frequency. Here we propose a continuum mechanical model for a viscoelastic medium, able to bridge atomic and macroscopic scale in amorphous materials and describe phonon attenuation due to atomistic mechanisms, characterized by a defined frequency dependence. This represents a first decisive step for investigating the effect of a complex nano- or microstructure on acoustic attenuation, while including the atomistic contribution as well.

Published
2020

20. Thermal transport across nanometre gaps: phonon transmission vs air conduction

Author

Fatemeh Tabatabaei, Christophe Adessi, Samy Merabia, S. Li, Konstantinos Termentzidis, Ali Alkurdi, Modélisation de la matière condensée et des interfaces (MMCI), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Laboratoire Énergies et Mécanique Théorique et Appliquée (LEMTA ), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Centre d'Energétique et de Thermique de Lyon (CETHIL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and Laboratoire d'Energétique et de Mécanique Théorique Appliquée (LEMTA )

Subjects
Materials science, Phonon, Orders of magnitude (temperature), FOS: Physical sciences, Near and far field, Near field heat transfer, 02 engineering and technology, Scanning thermal microscopy, 01 natural sciences, 010305 fluids & plasmas, Condensed Matter::Materials Science, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Lattice conduction, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Nanoscopic scale, ComputingMilieux_MISCELLANEOUS, Fluid Flow and Transfer Processes, Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, Mechanical Engineering, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, Condensed Matter Physics, Transition conduction/radiation, Thermal radiation, Heat transfer, Nanometre, Thermal transport across a gap, 0210 nano-technology
Abstract

Heat transfer between two surfaces separated by a nanometre gap is important for a number of applications ranging from spaced head disk systems, scanning thermal microscopy and thermal transport in aerogels. At these separation distances, near field radiative heat transfer competes with heat transfer mediated by phonons. Here we quantify the contribution of phonon assisted heat transfer between apolar solids using lattice dynamics combined with ab-initio calculations. We clearly demonstrate that phonons dominate heat transfer for subnanometre gaps. Strikingly, we conclude that even in the situation where the gap is filled with air molecules, phonons provide the dominant energy channel between the two solids nearly in contact. Our results predict orders of magnitude enhanced phonon heat transfer compared to previous works and bring forward a methodology to analyse phonon transmission across nanoscale vacuum gaps between apolar materials., 5 pages, 9 figures

Published
2020

21. First principle investigation of the influence of sulfur vacancies on thermoelectric properties of single layered MoS 2

Author

S. Thébaud, G. Bouzerar, Christophe Adessi, Stefano Pecorario, Université Claude Bernard Lyon 1 (UCBL), Université de Lyon, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), and Spectrométrie des biomolécules et agrégats (SPECTROBIO)

Subjects
[PHYS]Physics [physics], Materials science, Condensed matter physics, Phonon, Doping, General Physics and Astronomy, 02 engineering and technology, Electron, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, [SPI]Engineering Sciences [physics], Condensed Matter::Materials Science, Thermal conductivity, Vacancy defect, Thermoelectric effect, Figure of merit, First principle, [CHIM]Chemical Sciences, Condensed Matter::Strongly Correlated Electrons, Physical and Theoretical Chemistry, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology
Abstract

International audience; Thermoelectric properties of single layered transition metal dichalchogenide MoS2 are investigated on the basis of ab initio calculations combined with Landauer formalism. The focus is made on sulfur vacancy defects that are experimentally observed to be largely present in materials especially in exfoliated two dimensional MoS2 compounds. The impact of these defects on phonon and electron transport properties is investigated here using a realistic description of their natural disordering. It is observed that phonons tend to localize around defects which induce a drastic reduction in thermal conductivity. For p type doping the figure of merit is almost insensitive to the defects while for n type doping the figure of merit rapidly tends to be zero for the increasing length of the system. These features are linked with a larger scattering of the electrons in the conduction band than that of holes in the valence band.

Published
2020

22. Impact of structural complexity and disorder on lattice dynamics and thermal conductivity in the o- Al 13 Co 4 phase

Author

Lory, P.-F., Giordano, V., Gille, P., Euchner, H., Mihalkovič, M., Pellegrini, E., Gonzalez, M., Regnault, L.-P., Bastie, P., Schober, H., Pailhès, S., Johnson, M., Grin, Yu., De Boissieu, M., Institut Laue-Langevin (ILL), ILL, Science et Ingénierie des Matériaux et Procédés (SIMaP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Ludwig-Maximilians-Universität München (LMU), Helmholtz Institute Ulm (HIU), Slovak Acad. Sci., Inst. Phys. Bratislava, Inst. Physik, Slovak Academy of Science [Bratislava] (SAS), Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Max-Planck-Institut für Chemische Physik fester Stoffe (CPfS), Max-Planck-Gesellschaft, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Complex materials, Resonant inelastic x-ray scattering, Lattice dynamics, Lattice thermal conductivity, Quantum simulation, Molecular dynamics, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Quasicrystals, Inelastic neutron scattering
Abstract

International audience; Combining inelastic neutron and x-ray scattering with atomic scale simulation, we report on a comprehensive study of the lattice dynamics and its relationship with the low thermal conductivity of the o-Al13Co4 phase, a periodic approximant (about 100 atoms per cell) to a decagonal quasicrystal. The obtained experimental data, phonon lifetimes, and temperature-independent lattice thermal conductivity can only be fully described by molecular dynamics simulations, using oscillating pair potential, when the disorder of 12 Al sites is properly taken into account. Our results pave the way for a detailed understanding of materials where structural complexity and local disorder are at play.

Published
2020

23. Revisiting thin film of glassy carbon

Author

Martin Vondráčk, Florence Garrelie, Hatem Diaf, Christophe Donnet, Patrice Mélinon, Florent Bourquard, Antonio Pereira, Nicholas Blanchard, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Matériaux et nanostructures photoniques (MNP), Laboratoire Hubert Curien [Saint Etienne] (LHC), Université Jean Monnet [Saint-Étienne] (UJM)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS), Institute of Physics [Prague], Czech Academy of Sciences [Prague] (CAS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, and Institut d'Optique Graduate School (IOGS)-Université Jean Monnet [Saint-Étienne] (UJM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Physics and Astronomy (miscellaneous), Analytical chemistry, chemistry.chemical_element, Growth, 02 engineering and technology, Carbon nanotube, Glassy carbon, 01 natural sciences, [SPI.MAT]Engineering Sciences [physics]/Materials, law.invention, law, 0103 physical sciences, General Materials Science, Irradiation effects, Graphite, Thin film, 010306 general physics, Laser ablation, Graphene, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Amorphous solid, chemistry, 0210 nano-technology, Carbon
Abstract

Glassy carbon (GC) is a chemically stable form of fully $s{p}^{2}$-bonded carbon with locally ordered domains. GC is the intermediate material between graphite and diamond combining various properties such as high temperature resistance, hardness, good electrical conductivity, low density, low gases and liquids permeability, and excellent resistance to a wide range of aggressive chemical environments. These characteristics make it a very promising material for many applications, but unfortunately it is not widely used because of the high temperatures required for its synthesis. In this work, synthesis of glassy carbon thin films by means of laser ablation of carbon targets under vacuum or in gaseous helium, followed by a nanosecond laser irradiation of the deposited films, is presented. In particular, it is demonstrated that the amorphous structure of a thin film can be efficiently modified to the one of glassy carbon film by nanosecond UV laser irradiation. This method is valuable to prepare thin films similar to commercial glassy carbon with a completely different route which does not require the application of temperature beyond $1000{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$ which is not compatible with the silicon substrate for example. This opens for glassy carbon the way to microengineering applications (mechanics, electronics,$\ensuremath{\cdots}$). Particular attention is paid to characterize the vitreous carbon. In the literature, the vitreous nature of carbon layers is often highlighted on the basis of Raman spectroscopy measurements. However, as the Raman spectrum of glassy carbon is similar to that of pyrocarbon, multiwall carbon nanotubes, or functional graphene, this technique is not sufficient to safely characterize a carbonaceous material with a high degree of allotropy. To clear up any doubts, additional characterization methods, such as x-ray spectroscopy, transmission electron microscopy, and Rutherford backscattering spectrometry, are discussed here.

Published
2020

24. Anisotropic low-energy vibrational modes as an effect of cage geometry in the binary barium silicon clathrate Ba24Si100

Author

Viennois, Romain, Koza, Michael Marek, Debord, Régis, Toulemonde, Pierre, Mutka, Hannu, Pailhes, Stéphane, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Institut Laue-Langevin (ILL), ILL, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Matériaux, Rayonnements, Structure (MRS), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.MATE]Chemical Sciences/Material chemistry
Abstract

International audience; The low lattice thermal conductivity in inorganic clathrates has been shown recently to be related to the low-energy range of optical phonons dominated by motions of guest atoms trapped in a network of host covalent cages. A promising route to further reduce the heat conduction, and increase the material efficiency for thermoelectric heat waste conversion, is then to lower the energy of these guest-weighted optical phonons. In the present work, the effect of the host cage geometry is explored. The lattice dynamics of the binary type-IX clathrate, Ba24Si100, has been investigated experimentally by means of inelastic neutron scattering as a function of temperature between 5 K and 280 K, and computed by ab-initio density functional techniques. It is compared with the lattice dynamics of Ba8Si46, the simplest representative of the well-known type-I clathrate structure. The binary Ba8Si46 and Ba24Si100 materials have both a cubic unit cell made of different Si cages. The energies, the degree of anharmonicity as well as the anisotropy of the optical phonon modes weighted by Ba motions are found to depend strongly on 2 the size and shape of the cages. The lowest optical phonon energies in Ba24Si100 are found around 2.5-4 meV, while those in Ba8Si46 have higher energies around 7-9 meV. The low-lying optical phonons in Ba24Si100 are mainly weighted by the motion of Ba in the opened Si20 cage, which doesn't exist in Ba8Si46. Moreover, the Ba vibrations within the opened Si20 cages are found intrinsically anisotropic, strongly dispersionless in some directions and exhibit a significant anharmonicity, which is not observed for any optical phonon modes in Ba8Si46.

Published
2020

25. Anisotropic low-energy vibrational modes as an effect of cage geometry in the binary barium silicon clathrate B a 24 S i 100

Author

Viennois, Romain, Koza, Michael Marek, Debord, Régis, Toulemonde, Pierre, Mutka, Hannu, Pailhes, Stephane, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2), Institut Laue-Langevin (ILL), ILL, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Matériaux, Rayonnements, Structure (MRS), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Lattice dynamics, Density functional theory, Phonons, [CHIM]Chemical Sciences, Neutron scattering
Abstract

International audience; The low lattice thermal conductivity in inorganic clathrates has been shown recently to be related to the low-energy range of optical phonons dominated by motions of guest atoms trapped in a network of host covalent cages. A promising route to further reduce the heat conduction, and increase the material efficiency for thermoelectric heat waste conversion, is then to lower the energy of these guest-weighted optical phonons. In the present work, the effect of the host cage geometry is explored. The lattice dynamics of the binary type-IX clathrate, Basub>24Si100, has been investigated experimentally by means of inelastic neutron scattering as a function of temperature between 5 and 280 K, and computed by ab initio density functional techniques. It is compared with the lattice dynamics of Ba8Si46, the simplest representative of the well-known type-I clathrate structure. The binary Ba8Si46 and Ba24Si100 materials have both a cubic unit cell made of different Si cages. The energies, the degree of anharmonicity as well as the anisotropy of the optical phonon modes weighted by Ba motions are found to depend strongly on the size and shape of the cages. The lowest optical phonon energies in Ba24Si100 are found around 2.5–4 meV, while those in Ba8Si46 have higher energies around 7–9 meV. The low-lying optical phonons in Ba24Si100 are mainly weighted by the motion of Ba in the opened Si20 cage, which does not exist in Ba8Si46. Moreover, the Ba vibrations within the opened Si20 cages are found intrinsically anisotropic, strongly dispersionless in some directions, and exhibit a significant anharmonicity, which is not observed for any optical phonon modes in Ba8Si46.

Published
2020

26. Elastic anomalies in glasses: Elastic string theory understanding of the cases of glycerol and silica

Author

Valentina M. Giordano, Fernando Lund, Ernesto Bianchi, Departamento de Fisica [USACH Santiago], Universidad de Santiago de Chile [Santiago] (USACH), Pontificia Universidad Católica de Chile (UC), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Centro para la Investigación Interdisciplinaria Avanzada en Ciencias de los Materiales- CIMAT (CIMAT), Departamento de Física, Facultad de ciencias Físicas y Matemáticas, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
[PHYS]Physics [physics], Length scale, Physics, Condensed Matter - Materials Science, Condensed matter physics, Scattering, Glasses, Low frequency vibration, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Disordered Systems and Neural Networks (cond-mat.dis-nn), 02 engineering and technology, Condensed Matter - Disordered Systems and Neural Networks, 021001 nanoscience & nanotechnology, 01 natural sciences, Elasticity, Elastic string, [SPI]Engineering Sciences [physics], Thermal conductivity, 0103 physical sciences, [CHIM]Chemical Sciences, Boson peak, Acoustic phonons, 010306 general physics, 0210 nano-technology
Abstract

We present an implementation of the analytical string theory recently applied to the description of glasses. These are modeled as continuum media with embedded elastic string heterogeneities, randomly located and randomly oriented, which oscillate around a straight equilibrium position with a fundamental frequency depending on their length. The existence of a length distribution reflects then in a distribution of oscillation frequencies which is responsible for the Boson Peak in the glass density of states. Previously, it has been shown that such a description can account for the elastic anomalies reported at frequencies comparable with the Boson Peak. Here we start from the generalized hydrodynamics to determine the dynamic correlation function $S(k,\omega)$ associated with the coherent, dispersive and attenuated, sound waves resulting from a sound-string interference. Once the vibrational density of states has been measured, we can use it for univocally fixing the string length distribution inherent to a given glass. The density-density correlation function obtained using such distribution is strongly constrained, and able to account for the experimental data collected on two prototypical glasses: glycerol and silica. The obtained string length distribution is compatible with the typical size of elastic heterogeneities previously reported for silica and supercooled liquids, and the atomic motion associated to the string dynamics is consistent with the soft modes recently identified in large scale numerical simulations as non-phonon modes responsible for the Boson Peak. The theory is thus in agreement with the most recent advances in the understanding of the glass specific dynamics and offers an appealing simple understanding of the microscopic origin of the latter, while raising new questions on the universality or material-specificity of the string distribution properties., Comment: 15 pages, 8 figures

Published
2020

27. P-type thermoelectric LaCrO3-based epitaxial films grown by molecular beam epitaxy

Author

Dong Han, Esperonnat, Marc D., Mohamed Bouras, Rahma Moalla, Claude Botella, Aziz Benamrouche, Geneviève Grenet, Bruno Canut, Regis Debord, Giordano, Valentina M., Stéphane Pailhès, Guillaume Saint-Girons, Romain Bachelet, BACHELET, Romain, Institut des Nanotechnologies de Lyon (INL), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-École Centrale de Lyon (ECL), Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], ComputingMilieux_MISCELLANEOUS, [PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]
Abstract

International audience

Published
2020

28. Overcoming the thermal stability limit of chalcogenide Phase‐Change Materials for high‐Temperature applications in GeSe$_{1−x}$ Te$_x$ thin films

Author

Thierry Farjot, Françoise Hippert, Christophe Licitra, Martina Tomelleri, Pierre Noé, Valentina M. Giordano, Nicolas Vaxelaire, Daniel Benoit, Jean-Baptiste Dory, Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire des matériaux et du génie physique (LMGP ), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), STMicroelectronics [Crolles] (ST-CROLLES), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), the bilateral program Alpha between CEA-Leti and ST Microelectronics, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Materials science, Chalcogenide, phase-change memories, 02 engineering and technology, 01 natural sciences, thermal stability, chemistry.chemical_compound, Phase change, [SPI]Engineering Sciences [physics], 0103 physical sciences, [CHIM]Chemical Sciences, General Materials Science, Thermal stability, Limit (mathematics), Thin film, 010302 applied physics, [PHYS]Physics [physics], business.industry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, metavalent bonding, chemistry, Optoelectronics, chalcogenides, 0210 nano-technology, business, GeSeTe
Abstract

International audience; The electrical, optical, and structural properties of GeSe1−xTex phase‐change materials thin films with 0.16 ≤ x ≤1 prepared by cosputtering of GeSe and GeTe targets are studied. The crystallization temperature of the films increases significantly when the Te content decreases. Se‐rich films show an extremely large electrical contrast between their amorphous and crystalline states. A high polarizability of the crystalline phase is observed in the entire x range and is related to the presence of metavalent bonds. This is explained by the persistence of a rhombohedral crystalline phase, isostructural to GeTe, in the GeSe1−xTex films down to x = 0.16. Hence, the substitution of only 16 at% of the Se atoms by Te atoms transforms the covalent GeSe into a phase‐change material with a huge and unprecedented contrast of resistivity (up to 11 orders of magnitude) and a very high thermal stability (up to 10 years at 272 °C) for an alloy exhibiting no phase separation upon crystallization. This outstanding combination of properties makes Se‐rich GeSe1−xTex thin films extremely promising for integration in memory devices requiring a very high data retention such as automotive and embedded applications.

Published
2020

29. Unique silica polymorph obtained under electron irradiation

Author

Olivier Cavani, Daniel R. Neuville, Sylvie Le Floch, Imène Reghioua, Nadège Ollier, Matthieu Lancry, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Physics and Astronomy (miscellaneous), Analytical chemistry, chemistry.chemical_element, 02 engineering and technology, 01 natural sciences, Oxygen, symbols.namesake, Metamictization, [SPI]Engineering Sciences [physics], Phase (matter), 0103 physical sciences, Electron beam processing, [CHIM]Chemical Sciences, Irradiation, 010302 applied physics, [PHYS]Physics [physics], [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Crystallographic defect, chemistry, High pressure, symbols, 0210 nano-technology, Raman spectroscopy, [CHIM.RADIO]Chemical Sciences/Radiochemistry
Abstract

International audience; High purity synthetic silica glass (Suprasil F300) samples were densified by High Pressure/High Temperature (HP-HT) using three different pressure/temperature/duration values. Their relaxation process was studied by applying 2.5 MeV electron irradiation with doses varying from 1 MGy up to 11 GGy. At very high dose (11 GGy), all the densified silica samples exhibit the same density value (∼2.26 g/cm3) regardless of the densification conditions, referring to an equilibrium value known as an amorphous silica metamict phase. In detail, the HP-HT silica samples were progressively dedensified from 1 GGy irradiation dose until reaching this equilibrium. Whatever the initial topological disorder revealed through Raman spectra, all silica samples present identical Raman spectra at 11 GGy, with high intensities of D1 and D2 components, attesting they reach one unique silica polymorph. Regarding the irradiation at high temperature (600 MGy, 600 K), the results show that the thermal annealing during irradiation “accelerates” somehow the relaxation kinetics of both macroscopic density and vibrational signature. Furthermore, it seems that such high irradiation temperatures lead to increase the Non-Bridging Oxygen Hole Center point defects generation.The National Network EMIR was acknowledged for supporting the irradiation experiments in SIRIUS (No. 18-6129). The authors would like to thank l'Ecole Polytechnique for the junior postdoctoral grant. DEFI CNRS “Instrumentation aux Limites” was thanked for funding the Ultra-Bragg project.

Published
2019

30. Quantum transport properties of gas molecules adsorbed on Fe doped armchair graphene nanoribbons: A first principle study

Author

Hachemi Zitoune, M. Samah, Christophe Adessi, Lotfi Benchallal, Université Mohamed Akli Ouelhadj de Bouira (UMAOB), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Université Abderrahmane Mira [Béjaïa], and Université des Sciences et de la Technologie Houari Boumediene [Alger] (USTHB)

Subjects
Fe doped graphene nanoribbons, Materials science, 02 engineering and technology, 010402 general chemistry, DFT, 01 natural sciences, law.invention, [SPI]Engineering Sciences [physics], Adsorption, Impurity, law, Phase (matter), [CHIM]Chemical Sciences, General Materials Science, [PHYS]Physics [physics], Valence (chemistry), Spin polarization, ab initio, Graphene, Doping, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Gas adsorption, Electronic transport, Chemical physics, Gas sensor, 0210 nano-technology, Graphene nanoribbons
Abstract

International audience; Graphene, when doped with transition metals, is considered, both experimentally and theoretically, as a good candidate for the detection of gas molecules as CO, CO2, NO or NO2. This opens new perspectives for gas sensor set-ups considering that devices based on 2 dimensional graphene are more sensitive to detect molecules than solid-state gas sensors. The state of the arts on gas adsorption on Fe doped armchair graphene nanoribbons (Fe-AGNR) is still in its starting phase and thorough investigations of the mechanism of the adsorption on graphene need to be done. In the present work, the electronic and transport properties of molecules adsorbed on Fe-AGNR are scrutinized using ab-initio calculations. We observe that the adsorption of gas molecules on Fe-AGNR changes significantly the electronic properties of both the valence and the conduction band. Besides, The adsorbed molecules change the local electron density of states of the graphene nanoribbons, modifying thus the conductivity, being one of the main output quantity of the gas sensors. We also observe that the adsorbed molecules induce specific impurity bands which play a role in the transport properties. Finally, considering the observed variations of electrical conductance induced by the molecules, we propose several strategies to set-up gas sensors for CO, CO2, NO and NO2 molecules. These strategies are either based on the measurement of the conductance in the valence or the conduction band (using either p or n-doped Fe-AGNR) or to the spin polarization induced by the NO and NO2 molecules.

Published
2021

31. Thermal Transport in a 2D Nanophononic Solid: Role of bi-Phasic Materials Properties on Acoustic Attenuation and Thermal Diffusivity

Author

Luo, Haoming, Gravouil, Anthony, Giordano, Valentina, Tanguy, Anne, Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne] (LaMCoS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
numerical simulations, acoustic and thermal transfer, numerical simulations PACS: 62.20.-x, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], nanocomposite material, nanophononic material
Abstract

International audience; Nanophononic materials have recently arisen as a promising way for controlling heat transport, mirroring the results in macroscopic phononic materials for sound transmission, filtering and attenuation applications. Here we present a Finite Element numerical simulation of the transient propagation of an acoustic Wave-Packet in a 2D nanophononic material, which allows to identify the effect of the nanostructuration on the acoustic attenuation length and thus on the transport regime for the vibrational energy. Assuming elastic behavior in the matrix and in the inclusions, we find that the rigidity contrast between them not only tunes the apparent attenuation length of the wave packet along its main trajectory, but gives rise to different behaviours, from weak to strong scattering, and waves pinning. As a consequence, different energy transport regimes can be identified in the three-parameter space of the excitation frequency, inclusions size and rigidity contrast, leading to the identification of a combination of parameters allowing for the shortest attenuation distance. These results could have applications both in the field of acoustic insulation, and for the control of heat transfer.

Published
2019

32. Revisiting Pressure-Induced Transitions in Mesoporous Anatase TiO2

Author

Vittoria Pischedda, Denis Machon, Jérémie Margueritat, Laurence Bois, Quentin Martinet, Sylvie Le Floch, Alexis Forestier, Denis Morris, Lucien Saviot, Défi Jr.Jubgang Fandio, Laboratoire Nanotechnologies Nanosystèmes (LN2 ), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Sherbrooke (UdeS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS), Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke] (3IT), Université de Sherbrooke (UdeS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire des Multimatériaux et Interfaces (LMI), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Regroupement Québécois sur les Matériaux de Pointe (RQMP), École Polytechnique de Montréal (EPM)-Université de Sherbrooke (UdeS)-McGill University = Université McGill [Montréal, Canada]-Université de Montréal (UdeM)-Fonds Québécois de Recherche sur la Nature et les Technologies (FQRNT), Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Luminescence (LUMINESCENCE), Laboratoire Interdisciplinaire Carnot de Bourgogne (LICB), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Université de Sherbrooke (UdeS)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Phase transition, Anatase, Materials science, Nanoparticle, Oxides, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, [SPI]Engineering Sciences [physics], General Energy, Chemical engineering, Chemical structure, Phase transitions, Phase (matter), Nanoparticles, Physical and Theoretical Chemistry, Mesoporous material, Porosity
Abstract

International audience; Mesoporous materials may be considered as the negative image of a collection of nanoparticles. In both cases, the large surface area induces an increase of the system energy. Pressure-induced phase transitions are used to study the differences between mesoporous TiO 2 and a collection of TiO 2 nanoparticles. The synthesis and characterization of mesoporous TiO 2 with a nanosponge-like structure are presented and the inputs of different spectroscopic techniques (Terahertz, Brillouin and Raman) are highlighted. The results show that the phase stability of mesoporous TiO 2 under pressure is very similar to that observed in nanoparticles. 2

Published
2019

33. Ab initio investigation of the role of vanadium impurity states in SrTiO3 for thermoelectricity

Author

Richard Bouzerar, G. Bouzerar, Ch. Adessi, S. Thébaud, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Spectrométrie des biomolécules et agrégats (SPECTROBIO), and Université de Picardie Jules Verne (UPJV)

Subjects
Materials science, SrTiO3, Ab initio, Vanadium, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 7. Clean energy, 01 natural sciences, thermoelectricity, symbols.namesake, Thermal conductivity, Impurity, Seebeck coefficient, Thermoelectric effect, resonant states, General Materials Science, thermoelectric power factor, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Condensed matter physics, ab initio electronic transport, Doping, Fermi level, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, chemistry, oxides, symbols, 0210 nano-technology
Abstract

International audience; Despite their low cost, non-toxicity, thermal/chemical stability and relative abundance, oxides are not considered as promising materials for future thermoelectric devices. The main reason behind this lack of interest is their relatively high thermal conductivity. However, some oxides, such as n doped bulk SrTiO3 exhibit a rather good power factor. Keeping in mind that alloying and nanostructuring are two efficient procedures to suppress the thermal conductivity, it is worth exploring pathways towards an enhancement of the thermopower. Here, we report that vanadium doping of SrTiO3 gives rise to well defined resonant states allowing power factor of both n and p type over a relatively broad range of carrier concentrations. We investigate both the effects of a rigid band shift of the Fermi level and of realistic co-doping using DFT calculations.

Published
2019

34. Transport thermique dans un solide nanocomposite 2D: role des proprietes des materiaux bi-phasiques sur l'attenuation acoustique et la diffusivite thermique

Author

Haoming Luo, Anthony Gravouil, Anne Tanguy, Valentina M. Giordano, Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne] (LaMCoS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
acoustic and thermal transfer, Materials science, Sound transmission class, General Chemical Engineering, 02 engineering and technology, Thermal diffusivity, 62.20.-x, 01 natural sciences, Article, lcsh:Chemistry, numerical simulations, Rigidity (electromagnetism), 0103 physical sciences, General Materials Science, 010306 general physics, Scattering, Attenuation, Attenuation length, Mechanics, nanocomposite material, 021001 nanoscience & nanotechnology, lcsh:QD1-999, numerical simulations PACS: 62.20.-x, Heat transfer, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 0210 nano-technology, Acoustic attenuation, nanophononic material
Abstract

International audience; Nanophononic materials have recently arisen as a promising way for controlling heat transport, mirroring the results in macroscopic phononic materials for sound transmission, filtering and attenuation applications. Here we present a Finite Element numerical simulation of the transient propagation of an acoustic Wave-Packet in a 2D nanophononic material, which allows to identify the effect of the nanostructuration on the acoustic attenuation length and thus on the transport regime for the vibrational energy. Assuming elastic behavior in the matrix and in the inclusions, we find that the rigidity contrast between them not only tunes the apparent attenuation length of the wave packet along its main trajectory, but gives rise to different behaviours, from weak to strong scattering, and waves pinning. As a consequence, different energy transport regimes can be identified in the three-parameter space of the excitation frequency, inclusions size and rigidity contrast, leading to the identification of a combination of parameters allowing for the shortest attenuation distance. These results could have applications both in the field of acoustic insulation, and for the control of heat transfer.

Published
2019

35. Origin of dynamical instabilities in some simulated 2D Materials: GaSe as a case study

Author

Radescu, Silvana, Machon, Denis, Mélinon, Patrice, Universidad de La Laguna [Tenerife - SP] (ULL), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nanotechnologies et Nanosystèmes [Sherbrooke] (LN2), Université de Sherbrooke (UdeS)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke] (3IT), Université de Sherbrooke (UdeS), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)

Subjects
[PHYS]Physics [physics], [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]
Abstract

International audience; Following the emergence of 2D materials, a huge amount of work has been dedicated to this new class of materials. Numerical simulations have proven to be powerful to analyze and predict structure-properties relationships. However, a recurrent issue that arises in some 2D compounds is the appearance of a dynamical instability as an unstable phonon branch in a small pocket close the Brillouin zone center. The origin (numerical and/or physical) of this instability is hardly discussed. Here, using a rising 2D material, GaSe, as a case study, this issue is tackled by discussing the numerical techniques that may be used to lift the instability but also by understanding the fundamental origin of it. The interlayer distance is the crucial parameter and the ionicity of the compounds is the key physical property governing the propensity for instability. In many works, this distance is arbitrarily fixed to a value for which the absence of interactions between the periodic images of the layers is assumed. A careful control of the effect of this distance on the stability is required prior to subsequent calculations of physical properties.

Published
2019

36. Origin of dynamical instabilities in some simulated two-dimensional materials: GaSe as a case study

Author

S. Radescu, Denis Machon, Patrice Mélinon, Universidad de La Laguna [Tenerife - SP] (ULL), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nanotechnologies Nanosystèmes (LN2 ), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Sherbrooke (UdeS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS), Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke] (3IT), and Université de Sherbrooke (UdeS)

Subjects
Work (thermodynamics), Materials science, Physics and Astronomy (miscellaneous), Phonon, Dynamical instability, 2-dimensional systems, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Instability, Stability (probability), Physical property, Brillouin zone, Lift (force), 0103 physical sciences, Density functional theory, General Materials Science, Statistical physics, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, 0210 nano-technology
Abstract

International audience; Following the emergence of two-dimensional (2D) materials, a large amount of work has been dedicated to this class of materials. Numerical simulations have proven to be powerful to analyze and predict structure-properties relationships. However, a recurrent issue that arises in some 2D compounds is the appearance of a dynamical instability as an unstable phonon branch in a small pocket close to the Brillouin zone center. The origin (numerical and/or physical) of this instability is hardly discussed. Here, using a rising 2D material, GaSe, as a case study, this issue is tackled by discussing the numerical techniques that may be used to lift the instability but also by understanding the fundamental origin of it. The interlayer distance is the crucial parameter and the ionicity of the compounds is the key physical property governing the propensity for instability. In many works, this distance is arbitrarily fixed to a value for which the absence of interactions between the periodic images of the layers is assumed. A careful control of the effect of this distance on the stability is required prior to subsequent calculations of physical properties.

Published
2019

37. Large enhancement of the thermoelectric power factor in disordered materials through resonant scattering

Author

Georges Bouzerar, Ch. Adessi, S. Thébaud, Spectrométrie des biomolécules et agrégats (SPECTROBIO), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), and (nano)Matériaux pour l'énergie (ENERGIE)

Subjects
Chebyshev polynomials, FOS: Physical sciences, Tight-binding model, 02 engineering and technology, Power factor, 01 natural sciences, 7. Clean energy, Green's function methods, Atomic orbital, Seebeck coefficient, 0103 physical sciences, Electrical conductivity, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, Anisotropy, Physics, Condensed Matter - Materials Science, Condensed matter physics, Scattering, Materials Science (cond-mat.mtrl-sci), Thermoelectric systems, 021001 nanoscience & nanotechnology, Thermoelectric materials, Doped semiconductors, Thermoelectric generator, Thermopower, 0210 nano-technology
Abstract

In the search for more efficient thermoelectric materials, scientists have placed high hopes in the possibility of enhancing the power factor using resonant states. In this study, we investigate theoretically the effects of randomly distributed resonant impurities on the power factor. Using the Chebyshev Polynomial Green's Function method, we compute the electron transport properties for very large systems (10 million atoms) with an exact treatment of disorder. The introduction of resonant defects can lead to a large enhancement of the power factor together with a sign inversion in the Seebeck coefficient. This boost depends crucially on the position of the resonant peak, and on the interplay between elastic impurity scattering and inelastic processes. Strong electron-phonon or electron-electron scattering are found detrimental. Finally, the robustness of our results is examined in the case of anisotropic orbitals and two-dimensional confinement. Our findings are promising for the prospect of thermoelectric power generation., To appear in Phys. Rev. B

Published
2019

38. Porosity evolution of expanded vermiculite under pressure: the effect of pre-compaction

Author

A.N. Nguyen, Alfonso San-Miguel, Annie Brûlet, Sylvie Le Floch, Laurent Duclaux, Félix Balima, Laurence Reinert, Isabelle Daniel, Laurent Gremillard, Vittoria Pischedda, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Laboratoire LCME / Equipe Chimie Verte (LCME_CV), Laboratoire de Chimie Moléculaire et Environnement (LCME), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), University of Sciences [Ho Chi Minh City] (HCMC), Ho Chi Minh City University of Science (HCMUS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), LLB - Matière molle et biophysique (MMB), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), ANR-08-MAPR-0011,CELAJOAS,ComposÉs LAmellaires pour les JOints en Applications Sévères(2008), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Materials science, General Chemical Engineering, General Engineering, Compaction, General Physics and Astronomy, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, Vermiculite, 021001 nanoscience & nanotechnology, 01 natural sciences, Fractal dimension, 010305 fluids & plasmas, Stress (mechanics), 0103 physical sciences, General Earth and Planetary Sciences, General Materials Science, Lamellar structure, Texture (crystalline), Composite material, 0210 nano-technology, Anisotropy, Porosity, General Environmental Science
Abstract

International audience; The evolution of the pore structure of compressed expanded vermiculite was investigated in situ under uniaxial stress up to 3200 bar using small-angle neutron and X-ray scattering. The studied samples have a lamellar texture in which the presence of oriented oblate pores was revealed by the anisotropic small-angle scattering patterns. The initial pore size distribution and the mechanical behaviour of the pellets at working pressure conditions are strongly related to the applied initial stresses used to pre-compact the vermiculite powder. Our study shows that the porous structure of the pellets was not modified under compression up to the pre-compaction pressure. Higher densification is associated with increasing anisotropy of the pore–matrix interface structure. The pore–matrix interface could be described with fractal geometry. The stress dependence of the system fractal dimension, apparent specific surface area and total porosity was determined and related to the meso- and macropore evolution under uniaxial stress.

Published
2019

39. Structural and electronic changes in graphite fluorides as a function of fluorination rate: An XRS, PDF and DFT study

Author

Marc Dubois, Henry E. Fischer, Vittoria Pischedda, Nicolas Batisse, M. Vaughan, Michela Brunelli, Chiara Cavallari, S. Radescu, ESRF- The European Synchrotron Radiation Facility, Grenoble, Dutch-Belgian Beamline DUBBLE at the ESRF, Grenoble, Departamento de Física Fundamental II, MALTA Consolider Team, and Instituto de Materiales y Nanotecnología, Universidad de La Laguna, Departamento de Física Fundamental II, Institut de Chimie de Clermont-Ferrand (ICCF), SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), and European Synchroton Radiation Facility [Grenoble] (ESRF)

Subjects
Materials science, Neutron diffraction, Pair distribution function, chemistry.chemical_element, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, symbols.namesake, chemistry, symbols, Fluorine, Physical chemistry, [CHIM]Chemical Sciences, General Materials Science, Density functional theory, Graphite, 0210 nano-technology, Electronic band structure, Raman spectroscopy, Stoichiometry
Abstract

International audience; In the present paper, graphite fluoride compounds CxF with various degrees of fluorination (x = 4, 2 and 1), i.e., with different C-F bonding characteristics, were systematically investigated using X-ray Raman Spectroscopy (XRS) and X-ray and neutron diffraction by means of Pair Distribution Function (PDF) analysis. For both techniques, ab-initio calculations allow the experimental results and structural/bonding assignments to be explained and/or confirmed. Presented here for the three stoichiometries are results for the carbon and fluorine first-neighbour distances, the evolution of the electronic band structure due to the change of the carbon hybridization upon fluorination, and also the nature of the final states for 1s core-electron excitations. Since fluorination is limited by the diffusion of fluorine in the carbon lattice, the process is less effective in the bulk, where a graphitic core remains. The cross-checked XRS, PDF data and Density Functional Theory (DFT) simulations appear also to be a powerful method to highlight the presence of a residual graphitic core, even at the highest fluorine content, in such semi-disordered and structurally complex compounds.

Published
2019

40. Lattice Dynamics Study of Thermoelectric Oxychalcogenide BiCuChO (Ch = Se, S)

Author

David Berardan, Jean-Louis Bantignies, David Maurin, Mickael Beaudhuin, Romain Viennois, Céline Barreteau, Michael Marek Koza, Nita Dragoe, Patrick Hermet, Stéphane Pailhès, M. T. Fernandez-Diaz, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Charles Coulomb (L2C), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, and Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)

Subjects
Materials science, Condensed matter physics, Phonon, Anharmonicity, Neutron diffraction, 02 engineering and technology, Grüneisen parameter, 010402 general chemistry, 021001 nanoscience & nanotechnology, Thermoelectric materials, 7. Clean energy, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Brillouin zone, Condensed Matter::Materials Science, General Energy, Thermal conductivity, Thermoelectric effect, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, 0210 nano-technology
Abstract

jp9b04806_si_001.pdf (1.0 MB); International audience; The BiCuSeO-based compounds with very low thermal conductivity are among the most promising thermoelectric materials recently discovered. Their lattice dynamics, which remains mostly unexplored experimentally, is investigated in this paper. We report Raman experiments on BiCuSe1–xSxO solid solutions and infrared experiments on BiCuSeO and BiCuSO alloys coupled to first-principles-based calculations. We have observed that the high-energy A1g Raman-active mode strongly depends on the chalcogen content. We also report the density functional theory calculations of the dielectric and elastic constants, the phonons in the whole Brillouin zone, and the thermodynamic properties. We have determined the thermal expansion of BiCuSeO at room temperature from neutron diffraction experiments and evaluated its thermodynamic Grüneisen parameter and found a quite large value compared to other thermoelectric materials, which confirms the large anharmonicity of BiCuSeO.

Published
2019

41. Dynamics Properties of Photosynthetic Microorganisms Probed by Incoherent Neutron Scattering

Author

Alba-Simionesco, Christiane, Russo, Daniela, Lambreva, Maya Dimova, Simionesco, Christiane Alba, Sebban, Pierre, Rea, Giuseppina, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), Istituto di Cristallografia (IC), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie Physique D'Orsay (LCPO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), ILL, Consiglio Nazionale delle Ricerche (CNR), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Photosystem II, Plastoquinone, [SDV]Life Sciences [q-bio], Biophysics, single point mutation, Chlamydomonas reinhardtii, Protein dynamics, Photosynthesis, Purple bacteria, 03 medical and health sciences, Rhodobacter sphaeroides, chemistry.chemical_compound, [SPI]Engineering Sciences [physics], 0302 clinical medicine, [CHIM]Chemical Sciences, Chlorophyll fluorescence, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, [PHYS]Physics [physics], 0303 health sciences, photosynthesis, biology, neutron scattering, Chlamydomonas, Photosystem II Protein Complex, Articles, protein function, biology.organism_classification, Electron transport chain, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, Kinetics, Neutron Diffraction, chemistry, Mutation, 030217 neurology & neurosurgery
Abstract

International audience; Studies on the dynamical properties of photosynthetic membranes of land plants and purple bacteria have been previously performed by neutron spectroscopy, revealing a tight coupling between specific photochemical reactions and macro-molecular dynamics. Here, we probed the intrinsic dynamics of biotechnologically useful mutants of the green alga Chlamydomo-nas reinhardtii by incoherent neutron scattering coupled with prompt chlorophyll fluorescence experiments. We brought to light that single amino acid replacements in the plastoquinone (PQ)-binding niche of the photosystem II D1 protein impair electron transport (ET) efficiency between quinones and confer increased flexibility to the host membranes, expanding to the entire cells. Hence, a more flexible environment in the PQ-binding niche has been associated to a less efficient ET. A similar function/dynamics relationship was also demonstrated in Rhodobacter sphaeroides reaction centers having inhibited ET, indicating that flexibility at the quinones region plays a crucial role in evolutionarily distant organisms. Instead, a different functional/dynamical correlation was observed in algal mutants hosting a single amino acid replacement residing in a D1 domain far from the PQ-binding niche. Noteworthy, this mutant displayed the highest degree of flexibility, and besides having a nativelike ET efficiency in physiological conditions, it acquired novel, to our knowledge, phenotypic traits enabling it to preserve a high maximal quantum yield of photo-system II photochemistry in extreme habitats. Overall, in the nanosecond timescale, the degree of the observed flexibility is related to the mutation site; in the picosecond timescale, we highlighted the presence of a more pronounced dynamic heterogeneity in all mutants compared to the native cells, which could be related to a marked chemically heterogeneous environment.

Published
2019

42. Pressure-Induced Phase Transitions in TiO 2 Rutile Nanorods

Author

Stéphane Vignoli, Thibaut Cornier, Patrick Hermet, Stéphane Daniele, Denis Machon, Nicolas Le Bail, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire Nanotechnologies Nanosystèmes (LN2 ), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Sherbrooke (UdeS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-C'Durable (CDURABLE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Université de Sherbrooke (UdeS)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Phase transition, Materials science, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Nanomaterials, Condensed Matter::Materials Science, symbols.namesake, Chemical structure, Phase (matter), Metastability, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, [PHYS]Physics [physics], Oxides, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, General Energy, Rutile, Chemical physics, Phase transitions, symbols, Nanoparticles, Nanorod, Nanorods, 0210 nano-technology, Raman spectroscopy, Ambient pressure
Abstract

SSCI-VIDE+CDFA+TCO:SDA; International audience; TiO2 nanorods (diameter of 6–8 nm) with the rutile-type structure have been investigated by Raman spectroscopy under high pressure. Additional bands in the Raman spectrum at ambient pressure are interpreted as resulting from defects that break the Raman selection rules as the simulated vibrational density of states (vDOS) is in good agreement with the experimental spectrum. Under pressure, the rutile structure transforms to the baddeleyite one at P ∼ 16 GPa. After the pressure cycle, the α-PbO2 phase is recovered. The sequence of phases is discussed in terms of thermodynamics and kinetics based on crystallographic relationships. In contrast to other one-dimensional TiO2 nanomaterials that adopt a metastable structure, the nanorods studied in this work show little impact of the morphology on the phase transitions sequence compared to that of the bulk TiO2.

Published
2019

43. Enhancement and anticipation of the Ioffe-Regel crossover in amorphous/nanocrystalline composites

Author

Samy Merabia, Valentina M. Giordano, Anne Tanguy, Paul Desmarchelier, Ameni Tlili, Yaroslav M. Beltukov, Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne] (LaMCoS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), A.F. Ioffe Physical-Technical Institute, Russian Academy of Sciences [Moscow] (RAS), and Modélisation de la matière condensée et des interfaces (MMCI)

Subjects
Work (thermodynamics), Materials science, Nanocomposite, Condensed matter physics, Scattering, Phonon, Crossover, phonons, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 7. Clean energy, 0104 chemical sciences, Amorphous solid, Molecular dynamics, Thermal conductivity, nanocomposites, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science, thermal management, 0210 nano-technology
Abstract

International audience; Nanocomposites made of crystalline nanoinclusions embedded in an amorphous matrix are at the forefront of current research for energy harvesting applications. However, the microscopic mechanisms leading alternatively to an effectively reduced or enhanced thermal transport still escape understanding. In this work, we present a molecular dynamics simulation study of model systems, where for the first time we combine a microscopic investigation of phonon dynamics with the macroscopic thermal conductivity calculation, to shed light on thermal transport in these materials. We clearly show that crystalline nanoinclusions represent a novel scattering source for vibrational waves, modifying the nature of low energy vibrations and significantly anticipating the propagative-to-diffusive crossover (Ioffe–Regel), usually located at energies of few THz in amorphous materials. Moreover, this crossover position can be tuned by changing the elastic contrast between nanoinclusions and the matrix, and anticipated by a factor as large as 10 for a harder inclusion. While the propagative contribution to thermal transport is drastically reduced, the calculated thermal conductivity is not significantly affected in the chosen system, as the diffusive contribution dominates heat transport when all phonons are thermally populated. These findings allow finally to understand the panoply of contradictory results reported on thermal transport in nanocomposites and give clear indications to the characteristics that the parent phases should have for efficiently reducing heat transport in a nanocomposite.

Published
2019

44. Relaxation study of pre-densified silica glasses under 2.5 MeV electron irradiation

Author

Ollier, Nadège, Lancry, Matthieu, Martinet, Christine, Martinez, Valérie, Le Floch, Sylvie, Neuville, Daniel, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut Lumière Matière [Villeurbanne] (ILM), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), (nano)Matériaux pour l'énergie (ENERGIE), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), UltraBragg project funded by DEFI CNRS 'Instrumentation aux limites, Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), and Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
[PHYS]Physics [physics], [SPI]Engineering Sciences [physics], [CHIM]Chemical Sciences
Abstract

International audience; We examined the “relaxation properties” of pre-densified synthetic fused silica glass under 2.5 MeV electron irradiation. The densification of the glass was either obtained by hot compression (5 GPa-350 °C and 5 GPa-1000 °C) or via a thermal treatment increasing its fictive temperature (Tf = 1050, 1250 and 1400 °C). Under irradiation, the pre-densified silica glasses exhibit a relaxation of their macroscopic density with increasing integrated dose. Density was reduced for hot compressed silica and increased for Tf samples with different relaxation rates but it is remarkable that all sample densities follow a trend towards the same equilibrium value around 2.26 for a dose larger than 10 GGy despite a different final topology. After irradiation of hot compressed silica, the Raman spectra display a significant increment of 4 and almost 3-membered rings whereas they exhibit a glass density reduction; demonstrating that a D2 band increase cannot be considered as an absolute marker of the glass compaction. The correlation between density and D2 intensity remains valid until silica density remains lower than 2.26. In contrast, the FWHM of the main band peaking at 440 cm-1 appears to remain correlated to the silica glass density for all investigated samples.

Published
2019

45. Enhancement and anticipation of the Ioffe-Regel crossover in amorphous/nanocrystalline composites

Author

Tlili, Ameni, Giordano, Valentina, Beltukov, Yaroslav, Desmarchelier, Paul, Merabia, Samy, Tanguy, Anne, Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne] (LaMCoS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), A.F. Ioffe Physical-Technical Institute, Russian Academy of Sciences [Moscow] (RAS), and Modélisation de la matière condensée et des interfaces (MMCI)

Subjects
nanocomposites, phonons, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], thermal management
Abstract

International audience; Nanocomposites made of crystalline nanoinclusions embedded in an amorphous matrix are at the forefront of current research for energy harvesting applications. However, the microscopic mechanisms leading alternatively to an effectively reduced or enhanced thermal transport still escape understanding. In this work, we present a molecular dynamics simulation study of model systems, where for the first time we combine a microscopic investigation of phonon dynamics with the macroscopic thermal conductivity calculation, to shed light on thermal transport in these materials. We clearly show that crystalline nanoinclusions represent a novel scattering source for vibrational waves, modifying the nature of low energy vibrations and significantly anticipating the propagative-to-diffusive crossover (Ioffe–Regel), usually located at energies of few THz in amorphous materials. Moreover, this crossover position can be tuned by changing the elastic contrast between nanoinclusions and the matrix, and anticipated by a factor as large as 10 for a harder inclusion. While the propagative contribution to thermal transport is drastically reduced, the calculated thermal conductivity is not significantly affected in the chosen system, as the diffusive contribution dominates heat transport when all phonons are thermally populated. These findings allow finally to understand the panoply of contradictory results reported on thermal transport in nanocomposites and give clear indications to the characteristics that the parent phases should have for efficiently reducing heat transport in a nanocomposite.

Published
2019

46. Anisotropic mesoporous germanium nanostructures by fast bipolar electrochemical etching

Author

Richard Arès, Mohammad Reza Aziziyan, Arthur Dupuy, Abderraouf Boucherif, Denis Machon, Laboratoire Nanotechnologies et Nanosystèmes [Sherbrooke] (LN2), Université de Sherbrooke (UdeS)-École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut Interdisciplinaire d'Innovation Technologique [Sherbrooke] (3IT), Université de Sherbrooke (UdeS), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Nanostructure, Passivation, General Chemical Engineering, chemistry.chemical_element, Nanotechnology, Germanium, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Isotropic etching, 0104 chemical sciences, [SPI]Engineering Sciences [physics], chemistry, Etching (microfabrication), Specific surface area, Electrochemistry, 0210 nano-technology, Porosity, Mesoporous material, ComputingMilieux_MISCELLANEOUS
Abstract

Mesoporous germanium has received lately a growing interest in many fields. However, the lack of flexibility and knowledge concerning its electrochemical etching remains important. In this study, it is demonstrated the first synthesis of anisotropic porous morphologies using fast bipolar electrochemical etching (FBEE). The influence of the total porosification time, the etching density as well as the passivation time on the formation of tubular porous Ge (T-PGe) are investigated. It is also shown that is possible to modify T-PGe morphology by chemical etching to create Columnar Porous Germanium (C-PGe) that offers more opened porosity with lower specific surface area. Furthermore, we report the advantage of the electrochemical performances of C-PGe compared to T-PGe, when used as on-chip anodes for lithium-ion battery. Our findings demonstrate that by engineering the porous Ge morphology the cycle life of produced anodes could be extended by a factor 26 and 1.8 for high rate and high energy applications, respectively.

Published
2021

47. Thermoelectric perovskite-oxide epitaxial films grown by MBE

Author

Dong Han, Mohamed Bouras, Rahma Moalla, Claude Botella, Aziz Benamrouche, Grenet, G., Bruno Canut, Regis Debord, Valentina Giordano, Stéphane Pailhès, Romain Bachelet, Guillaume Saint-Girons, INL - Hétéroepitaxie et Nanostructures (INL - H&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), INL - Plateforme Technologique Nanolyon (INL - Nanolyon), INL - Spectroscopies et Nanomatériaux (INL - S&N), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-École Centrale de Lyon (ECL), Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE), and Saint-Girons, Guillaume

Subjects
[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], ComputingMilieux_MISCELLANEOUS
Abstract

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