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21 results on '"Palacio‐Morales, Alexandra"'

1. Coherent and incoherent tunneling into YSR states revealed by atomic scale shot-noise spectroscopy

Author

Thupakula, Umamahesh, Perrin, Vivien, Palacio-Morales, Alexandra, Cario, Laurent, Aprili, Marco, Simon, Pascal, and Massee, Freek

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Strongly Correlated Electrons
Abstract

The pair breaking potential of individual magnetic impurities in s-wave superconductors generates localized states inside the superconducting gap commonly referred to as Yu- Shiba-Rusinov (YSR) states whose isolated nature makes them ideal building blocks for artificial structures that may host Majorana fermions. One of the challenges in this endeavor is to understand their intrinsic lifetime, $\hbar/\Lambda$, which is expected to be limited by the inelastic coupling with the continuum thus leading to decoherence. Here we use shot-noise scanning tunneling microscopy to reveal that electron tunnelling into superconducting 2H-NbSe$_2$ mediated by YSR states is ordered as function of time, as evidenced by a reduction of the noise. Moreover, our data show the concomitant transfer of charges e and 2e, indicating that incoherent single particle and coherent Andreev processes operate simultaneously. From the quantitative agreement between experiment and theory we obtain $\Lambda$ = 1 $\mu$eV $\ll$ $k_BT$ demonstrating that shot-noise can probe energy- and time scales inaccessible by conventional spectroscopy whose resolution is thermally limited., Comment: 6 pages, 4 figures, Supplementary Information included as ancillary file

Published
2021
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2. Misfit layer compounds: a platform for heavily-doped two-dimensional transition metal dichalcogenides

Author

Leriche, Raphaël T., Palacio-Morales, Alexandra, Campetella, Marco, Tresca, Cesare, Sasaki, Shunsuke, Brun, Christophe, Debontridder, François, David, Pascal, Arfaoui, Imad, Šofranko, Ondrej, Samuely, Tomas, Kremer, Geoffroy, Monney, Claude, Jaouen, Thomas, Cario, Laurent, Calandra, Matteo, and Cren, Tristan

Subjects
Condensed Matter - Materials Science
Abstract

Transition metal dichalcogenides (TMDs) display a rich variety of instabilities such as spin and charge orders, Ising superconductivity and topological properties. Their physical properties can be controlled by doping in electric double-layer field-effect transistors (FET). However, for the case of single layer NbSe$_2$, FET doping is limited to $\approx 1\times 10^{14}$ cm$^{-2}$, while a somewhat larger charge injection can be obtained via deposition of K atoms. Here, by performing ARPES, STM, quasiparticle interference measurements, and first principles calculations we show that a misfit compound formed by sandwiching NbSe$_2$ and LaSe layers behaves as a NbSe$_2$ single layer with a rigid doping of $0.55-0.6$ electrons per Nb atom or $\approx 6\times 10^{14}$ cm$^{-2}$. Due to this huge doping, the $3\times3$ charge density wave is replaced by a $2\times2$ order with very short coherence length. As a tremendous number of different misfit compounds can be obtained by sandwiching TMDs layers with rock salt or other layers, our work paves the way to the exploration of heavily doped 2D TMDs over an unprecedented wide range of doping.

Published
2020
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3. Atomic-Scale Interface Engineering of Majorana Edge Modes in a 2D Magnet-Superconductor Hybrid System

Author

Palacio-Morales, Alexandra, Mascot, Eric, Cocklin, Sagen, Kim, Howon, Rachel, Stephan, Morr, Dirk K., and Wiesendanger, Roland

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Topological superconductors are predicted to harbor exotic boundary states - Majorana zero-energy modes - whose non-Abelian braiding statistics present a new paradigm for the realization of topological quantum computing. Using low-temperature scanning tunneling spectroscopy (STS), we here report on the direct real-space visualization of chiral Majorana edge states in a monolayer topological superconductor, a prototypical magnet-superconductor hybrid system comprised of nano-scale Fe islands of monoatomic height on a Re(0001)-O(2$\times$1) surface. In particular, we demonstrate that interface engineering by an atomically thin oxide layer is crucial for driving the hybrid system into a topologically non-trivial state as confirmed by theoretical calculations of the topological invariant, the Chern number., Comment: 26 pages, 9 figures

Published
2018
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4. Coupling of Coexisting Non-Collinear Spin States in the Fe Monolayer on Re(0001)

Author

Palacio-Morales, Alexandra, Kubetzka, André, von Bergmann, Kirsten, and Wiesendanger, Roland

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

Spin-polarized scanning tunneling microscopy is used to investigate the magnetic state of the Fe monolayer on Re(0001). Two coexisting atomic-scale non-collinear spin textures are observed with a sharp transition between them on the order of one atomic lattice spacing. A strict position correlation between the two spin states is observed both in experiments and in Monte Carlo simulations, demonstrating their strong coupling behavior., Comment: 5 pages, 3 figures

Published
2016
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5. Fermi Surface Reconstruction inside the Hidden Order Phase of URu2Si2 Probed by Thermoelectric Measurements

Author

Pourret, Alexandre, Palacio-Morales, Alexandra, Kramer, Steffen, Malone, Liam, Nardone, Marc, Aoki, Dai, Knebel, Georg, and Flouquet, Jacques

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

We report thermoelectric measurements of the low carrier heavy fermion compound URu2Si2 at high fields up to 34T and at low temperatures down to 500mK. The field dependence of the thermoelectric power (TEP) and the Nernst signal shows successive anomalies deep inside the hidden order (HO) phase. The field position of these anomalies correspond to different changes in the Shubnikov-de Haas frequencies and effective masses around 12 T, 17 T, 23 T and 30 T. These results indicate successive reconstructions of the Fermi surface, which imply electronic phase transitions well within the HO phase., Comment: 6 pages, 6 figures

Published
2013
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6. Surface phase nucleation of lead monoatomic layers on Si(111) Induced by manganese phthalocyanine molecules

Author

Longo, Danilo, Bocquet, Marie-Laure, Lorente, Nicolás, Cruguel, Hervé, Debontridder, F., Royer, Sébastien, David, Pascal, Palacio-Morales, Alexandra, Cren, T., Witkowski, Nadine, Brun, Christophe, Longo, Danilo, Bocquet, Marie-Laure, Lorente, Nicolás, Cruguel, Hervé, Debontridder, F., Royer, Sébastien, David, Pascal, Palacio-Morales, Alexandra, Cren, T., Witkowski, Nadine, and Brun, Christophe

Abstract

Hybrid interfaces where organic molecules are adsorbed on metallic substrates are very interesting to understand the fundamental interactions that might modify the chemical-physical properties of molecules or substrate. Here, we explore the adsorption of manganese phthalocyanines (MnPcs) on different structural phases of a Pb monatomic layer, namely, the √7 × √3-Pb and the striped incommensurate phase (SIC-Pb) phase, grown on Si(111). Surprisingly, the deposition of a minute amount of MnPc molecules (∼0.18 molecules/100 nm2) nucleates a macroscopic structural transition of the √7 × √3-Pb phase into the SIC-Pb phase. Our combined scanning tunneling microscopy, low-energy electron diffraction, and density functional theory study revealed that the mechanism behind this surface transformation is related to a strong and local molecule-substrate interaction. The structural phase transition is finally driven by the strained nature of the Pb phases and the energetic stability of the MnPc/SIC-Pb/Si(111) system with respect to the MnPc/√7 × √3-Pb/Si(111) one. The molecule-substrate interaction found in the present study is stronger than the one observed on Pb(111) bulk or thin films, highlighting the implication of the Pb/Si(111) interface in the interaction process. Hence, our results reveal that playing with the substrate dimensionality to tune the molecule-substrate coupling has strong impact on the electronic/magnetic properties of organic hybrid systems.

Published
2020

7. Misfit layer compounds: a platform for heavily doped 2D transition metal dichalcogenides

Author

Leriche, Raphaël T., Palacio‐Morales, Alexandra, Campetella, Marco, Tresca, Cesare, Sasaki, Shunsuke, Brun, Christophe, Debontridder, François, David, Pascal, Arfaoui, Imad, Šofranko, Ondrej, Samuely, Tomas, Kremer, Geoffroy, Monney, Claude, Jaouen, Thomas, Cario, Laurent, Calandra, Matteo, Cren, Tristan, Leriche, Raphaël T., Palacio‐Morales, Alexandra, Campetella, Marco, Tresca, Cesare, Sasaki, Shunsuke, Brun, Christophe, Debontridder, François, David, Pascal, Arfaoui, Imad, Šofranko, Ondrej, Samuely, Tomas, Kremer, Geoffroy, Monney, Claude, Jaouen, Thomas, Cario, Laurent, Calandra, Matteo, and Cren, Tristan

Abstract

Transition metal dichalcogenides (TMDs) display a rich variety of instabilities such as spin and charge orders, Ising superconductivity, and topological properties. Their physical properties can be controlled by doping in electric double‐layer field‐effect transistors (FET). However, for the case of single layer NbSe2, FET doping is limited to ≈1 × 1014 cm−2, while a somewhat larger charge injection can be obtained via deposition of K atoms. Here, by performing angle‐resolved photoemission spectroscopy, scanning tunneling microscopy, quasiparticle interference measurements, and first‐principles calculations it is shown that a misfit compound formed by sandwiching NbSe2 and LaSe layers behaves as a NbSe2 single layer with a rigid doping of 0.55–0.6 electrons per Nb atom or ≈6 × 1014 cm−2. Due to this huge doping, the 3 × 3 charge density wave is replaced by a 2 × 2 order with very short coherence length. As a tremendous number of different misfit compounds can be obtained by sandwiching TMDs layers with rock salt or other layers, this work paves the way to the exploration of heavily doped 2D TMDs over an unprecedented wide range of doping.

Published
2020

8. Misfit Layer Compounds: A Platform for Heavily Doped 2D Transition Metal Dichalcogenides

Author

Leriche, Raphaël T., primary, Palacio‐Morales, Alexandra, additional, Campetella, Marco, additional, Tresca, Cesare, additional, Sasaki, Shunsuke, additional, Brun, Christophe, additional, Debontridder, François, additional, David, Pascal, additional, Arfaoui, Imad, additional, Šofranko, Ondrej, additional, Samuely, Tomas, additional, Kremer, Geoffroy, additional, Monney, Claude, additional, Jaouen, Thomas, additional, Cario, Laurent, additional, Calandra, Matteo, additional, and Cren, Tristan, additional

Published
2020
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9. Surface Phase Nucleation of Lead Monoatomic Layers on Si(111) Induced by Manganese Phthalocyanine Molecules

Author

Longo, Danilo, primary, Bocquet, Marie-Laure, additional, Lorente, Nicolás, additional, Cruguel, Hervé, additional, Debontridder, François, additional, Royer, Sébastien, additional, David, Pascal, additional, Palacio-Morales, Alexandra, additional, Cren, Tristan, additional, Witkowski, Nadine, additional, and Brun, Christophe, additional

Published
2020
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11. Misfit Layer Compounds: A Platform for Heavily Doped 2D Transition Metal Dichalcogenides.

Author

Leriche, Raphaël T., Palacio‐Morales, Alexandra, Campetella, Marco, Tresca, Cesare, Sasaki, Shunsuke, Brun, Christophe, Debontridder, François, David, Pascal, Arfaoui, Imad, Šofranko, Ondrej, Samuely, Tomas, Kremer, Geoffroy, Monney, Claude, Jaouen, Thomas, Cario, Laurent, Calandra, Matteo, and Cren, Tristan

Subjects
*TRANSITION metals, *CHARGE density waves, *PHOTOELECTRON spectroscopy, *SCANNING tunneling microscopy, *FIELD-effect transistors, *CHARGE injection
Abstract

Transition metal dichalcogenides (TMDs) display a rich variety of instabilities such as spin and charge orders, Ising superconductivity, and topological properties. Their physical properties can be controlled by doping in electric double‐layer field‐effect transistors (FET). However, for the case of single layer NbSe2, FET doping is limited to ≈1 × 1014 cm−2, while a somewhat larger charge injection can be obtained via deposition of K atoms. Here, by performing angle‐resolved photoemission spectroscopy, scanning tunneling microscopy, quasiparticle interference measurements, and first‐principles calculations it is shown that a misfit compound formed by sandwiching NbSe2 and LaSe layers behaves as a NbSe2 single layer with a rigid doping of 0.55–0.6 electrons per Nb atom or ≈6 × 1014 cm−2. Due to this huge doping, the 3 × 3 charge density wave is replaced by a 2 × 2 order with very short coherence length. As a tremendous number of different misfit compounds can be obtained by sandwiching TMDs layers with rock salt or other layers, this work paves the way to the exploration of heavily doped 2D TMDs over an unprecedented wide range of doping. [ABSTRACT FROM AUTHOR]

Published
2021
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14. Thermoélectricité des composés fortement corrélés sous conditions extrêmes

Author

Palacio Morales, Alexandra, Service de Physique Statistique, Magnétisme et Supraconductivité (SPSMS - UMR 9001), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université de Grenoble, and Daniel Braithwaite

Subjects
Quantum criticallity, Electronic correlations, Thermoélectricité, Thermopower, Magnétisme, Magnetism, Fermions lourds, Criticalité quantique, Corrélations électroniques, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Heavy fermions, Nernst effect, Effect Nernst
Abstract

Thermopower is a technique whose importance is related to the possibility of directly measuring electronic properties of the systems, as it is sensitive to the derivative of the density of states. In this work, the low temperature regime of strongly correlated electron systems has been studied using this technique. For that, a new pressure-field thermopower device was developed, and used, to determine (T,P,H) phase diagrams of the itinerant ferromagnets UCoAl and UGe2, and of the weak antiferromagnet CeRh2Si2. For example, in the case of UCoAl, this same technique was used to analyze the metamagnetic transition from paramagnetic (PM) to ferromagnetic (FM) phases and to study its evolution towards the quantum critical end point. The existence of exotic magnetic excitations in the ground state and around the critical end point were also evidenced. On the compound CeRh2Si2, the suppression of the antiferromagnetic (AF) order by magnetic fields and pressures was explored. A strong change of the Fermi surface at Hc, the field at which the suppression of the AF into the paramagnetic polarized (PPM) phase, was observed. We show that under pressure, the magnetic fluctuations around the critical pressure Pc masked the Fermi surface reconstruction of the AF phase into the PM phase. The analysis of the (T,P,H) phase diagram revealed that the non-ordered phases of this compound (PM and PPM) are different, therefore pressure and field behave as different suppressor mechanisms. In the UGe2 compound, the analysis of its Fermi surface by thermopower quantum oscillations was performed as a last example of the utility and of the importance of this technique. To the best of the author knowledge, this is the first time that this technique was used in heavy fermion systems. A comparison to traditional probes such as de Haas-van Alphen and Shubnikov–de Haas effects was done. We observed a good agreement between them and we explain the advantages and the disadvantages of thermopower quantum oscillations technique over the traditional probes.; Cette thèse porte sous l'étude sous conditions extrêmes (basse température, fort champ magnétique et haute pression) des composés fortement corrélés du type fermions lourds. Trois composés ont été analysés UCoAl, UGe2 et CeRh2Si2, en utilisant principalement de mesures thermoélectriques; une technique récente et très sensible dans le domaine des fermions lourds. À cette fin, de nouvelles dispositives de mesures de pouvoir thermoélectricité sous pression ont été développés au cours de cette thèse.Concernant le composé d'UCoAl, notre étude a permis d'analyser précisément la transition metamagnétique, induite par le champ magnétique, entre la phase paramagnétique (PM) et la phase ferromagnétique (FM) ainsi que, son évolution sous pression. Ainsi, nos mesures ont permis de compléter le diagramme de phase (T,P,H) et notamment, de mettre en évidence la structure magnétique originale qui apparaît sous pression en forme de "wings" pas des mesures thermoélectriques. Une fine analyse de la surface de Fermi de la phase FM2 d'UGe2 a été réalisée grace à l'observation des oscillations quantiques du pouvoir thermoélectrique. Les résultats obtenues ont été comparés aux études conventionnelles des oscillations quantiques comme de "de Haas-van Alphen" (dHvA) et de "Suhbnikov-de Hass" (SdH) effets. Une très bonne accord entre les trois techniques a été constatée. % et montre les avantages d'utilisation des mesures du pouvoir thermoélectrique pour analyser les paramètres microscopiques des fermions lourds.% Les inconvénients de cette technique sont aussi présentés. Finalement, dans le système CeRh2Si2, la suppression du domaine antiferromagnétique (AF) sous champ magnétique Hc ∼ 26T et sous pression P∼1GPa a été étudiée. Un très fort changement de la surface de Fermi à Hc correspondant à la transition de l'ordre AF vers une phase paramagnétique polarisée (PPM), a été observé. Sous pression, des fluctuations magnétiques et une reconstruction de la surface de Fermi apparaissent autour de Pc. Ces fluctuations cachent la nature de la suppression de l'ordre AF vers un ordre paramagnétique (PM). L'étude du diagramme de phase (T,H,P) révèle que les phases PM et PPM sont différentes, cependant des points en commun demeurent.

Published
2014

15. Thermoelectricity of strongly correlated compounds under extreme conditions

Author

Palacio Morales, Alexandra, Service de Physique Statistique, Magnétisme et Supraconductivité (SPSMS - UMR 9001), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université de Grenoble, and Daniel Braithwaite

Subjects
Quantum criticallity, Electronic correlations, Thermoélectricité, Thermopower, Magnétisme, Magnetism, Fermions lourds, Criticalité quantique, Corrélations électroniques, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Heavy fermions, Nernst effect, Effect Nernst
Abstract

Thermopower is a technique whose importance is related to the possibility of directly measuring electronic properties of the systems, as it is sensitive to the derivative of the density of states. In this work, the low temperature regime of strongly correlated electron systems has been studied using this technique. For that, a new pressure-field thermopower device was developed, and used, to determine (T,P,H) phase diagrams of the itinerant ferromagnets UCoAl and UGe2, and of the weak antiferromagnet CeRh2Si2. For example, in the case of UCoAl, this same technique was used to analyze the metamagnetic transition from paramagnetic (PM) to ferromagnetic (FM) phases and to study its evolution towards the quantum critical end point. The existence of exotic magnetic excitations in the ground state and around the critical end point were also evidenced. On the compound CeRh2Si2, the suppression of the antiferromagnetic (AF) order by magnetic fields and pressures was explored. A strong change of the Fermi surface at Hc, the field at which the suppression of the AF into the paramagnetic polarized (PPM) phase, was observed. We show that under pressure, the magnetic fluctuations around the critical pressure Pc masked the Fermi surface reconstruction of the AF phase into the PM phase. The analysis of the (T,P,H) phase diagram revealed that the non-ordered phases of this compound (PM and PPM) are different, therefore pressure and field behave as different suppressor mechanisms. In the UGe2 compound, the analysis of its Fermi surface by thermopower quantum oscillations was performed as a last example of the utility and of the importance of this technique. To the best of the author knowledge, this is the first time that this technique was used in heavy fermion systems. A comparison to traditional probes such as de Haas-van Alphen and Shubnikov–de Haas effects was done. We observed a good agreement between them and we explain the advantages and the disadvantages of thermopower quantum oscillations technique over the traditional probes.; Cette thèse porte sous l'étude sous conditions extrêmes (basse température, fort champ magnétique et haute pression) des composés fortement corrélés du type fermions lourds. Trois composés ont été analysés UCoAl, UGe2 et CeRh2Si2, en utilisant principalement de mesures thermoélectriques; une technique récente et très sensible dans le domaine des fermions lourds. À cette fin, de nouvelles dispositives de mesures de pouvoir thermoélectricité sous pression ont été développés au cours de cette thèse.Concernant le composé d'UCoAl, notre étude a permis d'analyser précisément la transition metamagnétique, induite par le champ magnétique, entre la phase paramagnétique (PM) et la phase ferromagnétique (FM) ainsi que, son évolution sous pression. Ainsi, nos mesures ont permis de compléter le diagramme de phase (T,P,H) et notamment, de mettre en évidence la structure magnétique originale qui apparaît sous pression en forme de "wings" pas des mesures thermoélectriques. Une fine analyse de la surface de Fermi de la phase FM2 d'UGe2 a été réalisée grace à l'observation des oscillations quantiques du pouvoir thermoélectrique. Les résultats obtenues ont été comparés aux études conventionnelles des oscillations quantiques comme de "de Haas-van Alphen" (dHvA) et de "Suhbnikov-de Hass" (SdH) effets. Une très bonne accord entre les trois techniques a été constatée. % et montre les avantages d'utilisation des mesures du pouvoir thermoélectrique pour analyser les paramètres microscopiques des fermions lourds.% Les inconvénients de cette technique sont aussi présentés. Finalement, dans le système CeRh2Si2, la suppression du domaine antiferromagnétique (AF) sous champ magnétique Hc ∼ 26T et sous pression P∼1GPa a été étudiée. Un très fort changement de la surface de Fermi à Hc correspondant à la transition de l'ordre AF vers une phase paramagnétique polarisée (PPM), a été observé. Sous pression, des fluctuations magnétiques et une reconstruction de la surface de Fermi apparaissent autour de Pc. Ces fluctuations cachent la nature de la suppression de l'ordre AF vers un ordre paramagnétique (PM). L'étude du diagramme de phase (T,H,P) révèle que les phases PM et PPM sont différentes, cependant des points en commun demeurent.

Published
2014

17. Toward tailoring Majorana bound states in artificially constructed magnetic atom chains on elemental superconductors.

Author

Howon Kim, Palacio-Morales, Alexandra, Posske, Thore, Rózsa, Levente, Palotás, Krisztián, Szunyogh, László, Thorwart, Michael, and Wiesendanger, Roland

Subjects
*MAJORANA fermions, *QUANTUM computing, *CONDENSED matter, *TOPOLOGY, *ATOM lasers
Abstract

The article focuses on the study of majorana bound states (MBS) in condensed matter systems which is an important challenge focused on topological quantumcomputing. It focuses on the novel approach to design model-type atomic-scale systems for studying MBS by using single-atom manipulation techniques.

Published
2018
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20. Misfit layer compounds: a platform for heavily doped 2D transition metal dichalcogenides

Author

Leriche, Raphaël T., Palacio‐Morales, Alexandra, Campetella, Marco, Tresca, Cesare, Sasaki, Shunsuke, Brun, Christophe, Debontridder, François, David, Pascal, Arfaoui, Imad, Šofranko, Ondrej, Samuely, Tomas, Kremer, Geoffroy, Monney, Claude, Jaouen, Thomas, Cario, Laurent, Calandra, Matteo, Cren, Tristan, Leriche, Raphaël T., Palacio‐Morales, Alexandra, Campetella, Marco, Tresca, Cesare, Sasaki, Shunsuke, Brun, Christophe, Debontridder, François, David, Pascal, Arfaoui, Imad, Šofranko, Ondrej, Samuely, Tomas, Kremer, Geoffroy, Monney, Claude, Jaouen, Thomas, Cario, Laurent, Calandra, Matteo, and Cren, Tristan

Abstract

Transition metal dichalcogenides (TMDs) display a rich variety of instabilities such as spin and charge orders, Ising superconductivity, and topological properties. Their physical properties can be controlled by doping in electric double‐layer field‐effect transistors (FET). However, for the case of single layer NbSe2, FET doping is limited to ≈1 × 1014 cm−2, while a somewhat larger charge injection can be obtained via deposition of K atoms. Here, by performing angle‐resolved photoemission spectroscopy, scanning tunneling microscopy, quasiparticle interference measurements, and first‐principles calculations it is shown that a misfit compound formed by sandwiching NbSe2 and LaSe layers behaves as a NbSe2 single layer with a rigid doping of 0.55–0.6 electrons per Nb atom or ≈6 × 1014 cm−2. Due to this huge doping, the 3 × 3 charge density wave is replaced by a 2 × 2 order with very short coherence length. As a tremendous number of different misfit compounds can be obtained by sandwiching TMDs layers with rock salt or other layers, this work paves the way to the exploration of heavily doped 2D TMDs over an unprecedented wide range of doping.

21. Non-Fermi-liquid nature and exotic thermoelectric power in the heavy-fermion superconductor UBe13.

Author

Shimizu, Yusei, Pourret, Alexandre, Knebel, Georg, Palacio-Morales, Alexandra, and Aoki, Dai

Subjects
*URANIUM compounds, *FERMI liquids, *THERMOELECTRIC power, *HEAVY fermion superconductors, *MAGNETIC fields
Abstract

We report quite exotic thermoelectric power S in UBe13. At 0 T, the negative S/T continues to strongly enhance down to the superconducting transition temperature with no Fermi-liquid behavior. |S/T| is dramatically suppressed and becomes rather modest with increasing field. We have also obtained precise field dependencies of (i) an anomaly in S due to an exotic Kondo effect and (ii) a field-induced anomaly in S/T associated with the anomalous upward Hc2(T). In contrast to the field-sensitive transport property, the normal-state specific heat is magnetically robust, indicating that the largeness of the 5f density of states remains in high fields. This unusual behavior in UBe13 can be explained by a considerable change in the energy derivative of the conduction-electron lifetime tc(e) at the Fermi level under magnetic fields. [ABSTRACT FROM AUTHOR]

Published
2015
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