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This study presents an efficient methodology for simulating nonadiabatic dynamics of complex materials with excitonic effects by integrating machine learning (ML) models with simplified Tamm–Dancoff approximation (sTDA) calculations. By leveraging ML models, we accurately predict ground-state wavefunctions using unconverged Kohn–Sham (KS) Hamiltonians. These ML-predicted KS Hamiltonians are then employed for sTDA-based excited-state calculations (sTDA/ML). The results demonstrate that excited-state energies, time-derivative nonadiabatic couplings, and absorption spectra from sTDA/ML calculations are accurate enough compared with those from conventional density functional theory based sTDA (sTDA/DFT) calculations. Furthermore, sTDA/ML-based nonadiabatic molecular dynamics simulations on two different materials systems, namely chloro-substituted silicon quantum dot and monolayer black phosphorus, achieve more than 100 times speedup than the conventional linear response time-dependent DFT simulations. This work highlights the potential of ML-accelerated nonadiabatic dynamics simulations for studying the complicated photoinduced dynamics of large materials systems, offering significant computational savings without compromising accuracy. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries (LIBs) are the most crucial part of energy storage systems. The lower molar weight of anodes can achieve a higher theoretical capacity. We explore the performance of a Be2B monolayer as an anode for LIBs. By first-principles calculations, we reveal that the Be2B monolayer shows excellent tensile strength, which suggests that it can deal with the volume expansion during the adsorption process. Furthermore, the Be2B monolayer can stably adsorb Li atoms with an adsorption energy of −0.98 eV. Moreover, the Be2B monolayer exhibits a low diffusion barrier (0.066 eV), an ultra-high theoretical capacity (3717 mA h g−1), and a moderate open circuit voltage (0.59 V). We also confirm the wettability of the Be2B monolayer in common electrolytes and investigate the adsorption and diffusion properties of Li on Be2B/graphene heterostructure. The introduction of graphene enhances the migration behavior of Li, suggesting the fast charging/discharging capability. Based on the above-mentioned properties, we propose that the Be2B monolayer can act as a high-performance anode material. [ABSTRACT FROM AUTHOR]

A benchmark model that combines an embedded-cluster approach for ionic surfaces with wavefunction-based methods to predict the vibrational frequencies of molecules adsorbed on surfaces is presented. As a representative case, the adsorption of CO on the lowest index non-polar and most stable facet of CeO 2 , that is, (111) was studied. The CO harmonic vibrational frequencies were not scaled semiempirically but explicitly corrected for anharmonic effects, which amount to about 25 cm − 1 with all tested methods. The second-order Møller–Plesset perturbation method (MP2) tends to underestimate the CO harmonic frequency by about 40–45 cm − 1 in comparison with the results obtained with the coupled-cluster singles and doubles with perturbational treatment of triple excitation method [CCSD(T)] and independently from the basis set used. The best estimate for the CO vibrational frequency (low-coverage case) differs by 12 cm − 1 with the experimental value obtained by infrared reflexion absorption spectroscopy of 1 monolayer CO adsorbed on the oxidized CeO 2 (111) surface. In addition, a conservative estimate of the adsorption energy of about −0.22 ± −0.07 eV obtained at the CCSD(T) level confirms the physisorption character of the adsorption of CO on the CeO 2 (111) surface. [ABSTRACT FROM AUTHOR]

Raman and PL (photoluminescence) spectroscopy are effective techniques for characterizing the physical properties of transition metal dichalcogenides (TMDCs). Modulating intensities of these optical signals is crucial for the advancement of research and the subsequent application of TMDCs. However, it is challenging to continuously modulate optical signals' intensities. Herein, by using a wedge-like SiO2/Si substrate, the intensities of optical signals of monolayer MoS2 are enhanced continuously, which results in ~22 times and ~39 times gain in E 2 g 1 and A1g Raman mode, respectively, and a ~13 times gain in the PL intensity. The results are of significant importance for monolayer TMDCs' characterization and applications, e.g., optoelectronics. [ABSTRACT FROM AUTHOR]

Aiming at exploring whether the Janus structure is beneficial to improving the thermoelectric (TE) performance, we systematically study the TE properties of the α -Se-monolayer-based Janus structures including α - SSe 2 and α - TeSe 2 monolayers. In comparison with the semiconducting α -Se monolayer, the Janus α - SSe 2 and α - TeSe 2 monolayers are still kept to be indirect semiconductors but with suppressed energy bandgaps. Moreover, the phononic thermal conductance will be suppressed with other parameters like Seebeck coefficients, electrical conductances, and electronic thermal conductances being changed correspondingly. The TE figures of merit Z T s of the Janus α - SSe 2 and α - TeSe 2 monolayers are always greater than that of the α -Se monolayer, indicating that the Janus structure should be a potential scheme used to improve the TE performance of materials. [ABSTRACT FROM AUTHOR]

A monolayer of 4-nitrothiophenol adsorbed on an Au substrate was heated by illuminating the substrate with a 19 ps laser pulse of 532 nm wavelength. Within 91 ps, the temperature of the sample increased from room temperature by 113 K. Vibrational sum frequency spectroscopy was used to characterize the adsorption geometry of the molecules in the ordered domains in the monolayer film. Upon heating, the initially ordered monolayer largely lost its structure. While the molecules are initially tilted by about 50° with respect to the surface normal, the analysis indicates that the mean tilt angle increased to 80° with a spread for individual molecules of up to a tilt angle of 40° upon heating. The evolution of this loss of order lagged about 100 ps behind the temperature rise of the substrate. [ABSTRACT FROM AUTHOR]

The electrocatalytic performance of VSe2 doped with nonmetals (NMs) was studied using density functional theory, in which NM atoms (C, N, O, P, S, F, Cl, Br, and I) replaced Se or V (denoted as NM@Se or NM@V). Notably, P@V and Br@V monolayers exhibit high catalytic hydrogen evolution reaction activity with the lowest ΔGH* = 0.08 eV and −0.03 eV, respectively, surpassing Pt (ΔGH* = −0.1 eV). By applying the scaling relationship of ΔGH* of H*, which is an intermediate for each volcano, the exchange current density diagrams are established. Based on thermodynamic analysis, P@V and Br@V monolayers produce exchange currents of about −1.42 and −0.70i0/(A cm−2), respectively. The oxygen evolution reaction activity of the I@Se monolayer (ηOER = 0.95 V) is the best among all the monolayers. Among the oxygen reduction reaction catalysts, the O@Se monolayer displays high activity with a low ηORR (0.82 V), which is even better than that of binary Pt and Pd alloys (0.9–0.87 V). [ABSTRACT FROM AUTHOR]

Polyethyleneimine (PEI) is a widely used cationic polyelectrolyte. In organic electronics, it is a universal surface modifier for shifting the electrode work function (Φ) and improving charge injection into electronic devices. This effect may depend on the conformation and dipolar order of the PEI ultrathin film, but their detailed experimental evaluation has not yet been reported. Thus, we used sum-frequency generation (SFG) spectroscopy to probe the net orientation of polar groups of PEI films on glass and gold. The films were fabricated by spin-coating from alcoholic solutions or by dip-coating from aqueous solutions of various pH values, with both branched (b-PEI) and linear (l-PEI) structures. The obtained SFG spectra and atomic force microscopy (AFM) images indicated that the conformational ordering of the PEI layers increases over the period of 14 days after fabrication, being slightly more pronounced for l-PEI vs b-PEI, and for dip-coating vs spin coating fabrication. Furthermore, both the pH of the dip-coating solutions and the substrate nature influence the final morphology and order of the adsorbed films. On glass, they are optimized at an intermediate pH 5, while on gold, the greatest homogeneity is observed at pH 2 and the largest dipolar order is observed at pH 10. The pH dependence of changes in the work function of gold by PEI (|ΔΦ|) suggests that the electronic contribution is dominant. Nevertheless, the evolution of the PEI dipolar ordering was accompanied by small variations of |ΔΦ|, suggesting that it does have a significant contribution, especially at conditions for which the electronic contribution is reduced. [ABSTRACT FROM AUTHOR]

Comprehending the relationship between spin and phonons is essential to regulate the lattice thermal conductivity in 2D magnetic materials. Lattice thermal conductivity is a relevant part to consider in magnetic data storage and the working of spin-based devices. In this article, we examined the origin and effect of spin–phonon coupling (SPC) on the lattice thermal conductivity of pristine CrI 3 monolayer-based Janus monolayers Cr 2 X 3 S 3 (X = Br , I). We find a high SPC in these Janus monolayers due to in-plane Cr–S atomic vibrations. We observe a reduction in the lattice thermal conductivity at Janus monolayer magnetic states (∼ 52.3 % in Cr 2 Br 3 S 3 and ∼ 63.9% in Cr 2 I 3 S 3) compared to its paramagnetic states. The analysis is also conducted to determine which magnetic state has more anharmonicity using potential energy wells. A wide range of 2D magnetic materials can benefit from our results in the future development of spin-based thermal devices. [ABSTRACT FROM AUTHOR]

Phospholipase A2 (PLA2) catalyzes the hydrolysis of the sn-2 acyl ester linkage in phospholipid, producing lysophospholipid and fatty acid in the presence of Ca2+. The hydrolysis mediated by PLA2 has attracted much interest in various fields, such as pharmacy and biotechnology. It is recognized that PLA2 cannot hydrolyze phospholipid monolayers at high surface coverage. However, the origin of different PLA2 activities is not fully understood yet. The present study investigated the interaction between DPPC (16:0 PC) monolayer and PLA2 using heterodyne-detected sum frequency generation spectroscopy, which is interface-specific spectroscopy and highly sensitive to molecular symmetry based on a second-order nonlinear optical process. It was revealed that PLA2 adsorbs to the DPPC monolayer on the aqueous solution surface only when the surface coverage is low. The adsorption at the low surface coverage significantly changes the interfacial structures of PLA2 and the hydration, which are stabilized by the presence of Ca2+. Therefore, the restriction of the hydrolysis of phospholipid monolayers at high surface coverage can be rationalized by the inhabitation of the PLA2 adsorption. The present study deepens our molecular-level understanding of the hydrolysis of phospholipids by PLA2. [ABSTRACT FROM AUTHOR]

In this study, we investigated the thermoelectric properties of molecular junctions, created by trapping naphthacene (C18H12) and rubrene (C42H28) molecules between two graphene electrodes. It is found that the charge transport of naphthacene-based and rubrene-based graphene junctions is not sensitive to the introduction of edge side branches or the increase in molecular length and still maintains resonance transport at the Fermi level. Notably, the presence of pendant branches on the molecular trunk in rubrene-based graphene junctions leads to a suppression of phonon transport, attributed to multiple scattering at the branch attachment points or Fano resonance scattering. The phonon thermal conductance of the rubrene junctions can be reduced by nearly half compared to that of naphthalene junctions. Furthermore, the room-temperature figure of merit (ZT) is significantly enhanced from 0.2 to 1.1 upon constructing weak coupling junctions, representing an almost tenfold increase over covalent junctions. These findings mean that it is highly desirable to find a mechanism that can suppress the phonon thermal conductance of self-assembled molecular films, while preserving their power factor at optimal levels to obtain high-efficiency thermoelectric performance. [ABSTRACT FROM AUTHOR]

Chemical and physical processes on the surfaces of amorphous solids have been the focus of many studies over the past decades. These studies have established that dynamics in a thin layer near a glass surface are often dramatically faster than those in the glass bulk. Nevertheless, recent advances also emphasize the need for new experimental techniques capable of characterizing the structure and dynamics of the near-surface regions in glassy materials at the molecular length scale. Using a quasi-adiabatic fast scanning calorimetry (FSC) technique, we have investigated softening and vaporization of pure amorphous methylbenzene films of moderately heightened kinetic stability with thicknesses ranging from 1 to 20 nm. The analysis of the FSC thermograms reveals the existence of a high fictive temperature (liquid-like) layer on the surface of the solid glass with a thickness of 3.5 ± 0.5 nm or seven molecular diameters. Furthermore, the width of the boundary between liquid-like and solid layers in the films is less than 1 nm. These preliminary findings compliment and substantiate past determinations of the mobile surface layer thicknesses obtained by introduction of nanoparticles or spectroscopic molecular probes to near-surface regions of amorphous samples. The developed FSC methodology will advance the theoretical and computational research by providing calorimetric data on the enhanced interfacial dynamics phenomenon in a variety of low-molecular-weight amorphous materials. [ABSTRACT FROM AUTHOR]

This study delves into the interplay of symmetry and structure in 2D systems to identify monolayers hosting valley physics together with the Rashba effect. Through high-throughput density functional theory calculations, 57 monolayers are identified exhibiting the Rashba effect, with the Rashba parameter α R spanning from 0 < α R < 2.0. The robustness of the Rashba parameters (α R) in these monolayers is primarily influenced by the physical parameters, highlighting the anti-crossing of Rashba-split bands and the Born effective charge (Z*). Among the 57 monolayers exhibiting the Rashba effect, the study identifies a subset of 23 monolayers presenting valley physics, demonstrating both in-plane and out-of-plane spin polarizations. The pronounced coupling of the valley and Rashba spin splitting is influenced by the in-plane and out-of-plane orbital contributions at the relevant K-points in the band spectra. In particular, the AB-type buckled structures feature these dual properties due to the presence of the broken inversion and mirror symmetries in them. Overall, the study eases the identification of monolayers with significant spin splitting and spin polarization, aiding in the design of high-performance 2D materials. [ABSTRACT FROM AUTHOR]

Designing coatings and films that can protect surfaces is important in a wide variety of applications from corrosion prevention to anti-fouling. These systems are challenging from a modeling perspective because they are invariably multicomponent, which quickly leads to an expansive design space. At a minimum, the system has a substrate, a film (often composed of a polymeric material), a ubiquitous carrier solvent, which may be either a vapor or liquid phase, and one or more contaminants. Each component has an impact on the effectiveness of coating. This paper focuses on films that are used as a barrier to surface contamination, but the results also extend to surface coatings that are designed to extract a low density species from the fluid phase as in liquid chromatography. A coarse-grained model is developed using Yukawa potentials that encompasses both repulsive and attractive interactions among the species. Classical density functional theory calculations are presented to show how contaminant adsorption is controlled by the molecular forces in the system. Two specific vectors through the parameter space are considered to address likely experimental manipulations that change either the solvent or the polymer in a system. We find that all the adsorption results can be unified by considering an appropriate combination of molecular parameters. As a result, these calculations provide a link between molecular interactions and film performance and may serve to guide the rational design of films. [ABSTRACT FROM AUTHOR]

This study investigates the impact of biaxial strain on monolayer black phosphorus (BP) through first-principles calculations, confirming its stability and subsequently modifying its photocatalytic performance. Under biaxial strain, BP exhibits a direct bandgap suitable for photocatalytic hydrogen production during water splitting, albeit with limitations due to its valence band maximum edge. A distinctive GaN/BP heterojunction is proposed, featuring a direct bandgap and advantageous band edge positions conducive to efficient photocatalytic overall water splitting. Under the influence of biaxial strain, the heterojunction type undergoes a transition from direct type-I to direct type-II and Z, augmenting the separation of photoexcited electrons and holes and markedly enhancing the efficiency of photocatalytic hydrogen production. Furthermore, the heterojunction exhibits commendable capabilities in absorbing visible light. This research provides a promising avenue to surmount the constraints associated with monolayer BP in photocatalysis, offering valuable insights for the development of efficient photocatalytic materials. [ABSTRACT FROM AUTHOR]

MoSi2N4 is a two-dimensional ternary nitride semiconductor that has attracted attention for its excellent mechanical and thermal properties. Theoretical studies predict that zigzag edges of this material can host magnetic edge states and Dirac fermions, but the stability of such edges has not been examined. Here, we present a density functional theory study of the electronic and thermodynamic properties of MoSi2N4 edges. We develop a (partial) ternary phase diagram that identifies a region of chemical potentials within which MoSi2N4 is stable over competing elemental or binary phases. Based on this phase diagram, we determine the thermodynamic stability of several armchair and zigzag edges and elucidate their electronic structures. Bare zigzag edges, predicted to host exotic electronic states, are found to be substantially higher in energy than armchair edges and, thus, unlikely to occur in practice. However, with hydrogen passivation, these zigzag edges can be stabilized relative to their armchair counterparts while retaining metallicity and magnetic order. Our analysis provides a solid thermodynamic basis for further exploration of MoSi2N4 in nanoscale electronics and spintronics. [ABSTRACT FROM AUTHOR]

MoSi2N4 is a two-dimensional ternary nitride semiconductor that has attracted attention for its excellent mechanical and thermal properties. Theoretical studies predict that zigzag edges of this material can host magnetic edge states and Dirac fermions, but the stability of such edges has not been examined. Here, we present a density functional theory study of the electronic and thermodynamic properties of MoSi2N4 edges. We develop a (partial) ternary phase diagram that identifies a region of chemical potentials within which MoSi2N4 is stable over competing elemental or binary phases. Based on this phase diagram, we determine the thermodynamic stability of several armchair and zigzag edges and elucidate their electronic structures. Bare zigzag edges, predicted to host exotic electronic states, are found to be substantially higher in energy than armchair edges and, thus, unlikely to occur in practice. However, with hydrogen passivation, these zigzag edges can be stabilized relative to their armchair counterparts while retaining metallicity and magnetic order. Our analysis provides a solid thermodynamic basis for further exploration of MoSi2N4 in nanoscale electronics and spintronics. [ABSTRACT FROM AUTHOR]

As a newly synthesized two-dimensional (2D) carbon material, monolayer quasi-hexagonal phase fullerene (qHP C60) has an excellent electronic structure and low thermal conductivity. qHP C60 attracted significant attention from scientists because it has potential applications in thermoelectric materials. Thermoelectric properties of 2D materials significantly depend on the transport of carriers (such as electrons and phonons), and strain engineering is an essential method for modulating the transport of electrons and phonons in 2D materials. However, the strain engineering method for the modulation of the thermoelectric properties of monolayer qHP C60 has not been reported yet. In the present paper, the first-principles combined with the non-equilibrium Green's function method are used to investigate the ballistic transport properties of electrons and phonons in monolayer qHP C60. The effects of temperature, chemical potential, and biaxial tensile strain on the thermoelectric transport parameters (including conductivity, Seebeck coefficient, power factor, and thermal conductivity) as well as the figure of merit (ZT) of monolayer qHP C60 are presented, compared, discussed, and analyzed. We found that monolayer qHP C60 exhibits anisotropic characteristics in electron and phonon transport properties, showcasing outstanding thermoelectric properties. The distinctive quasi-hexagonal phase fullerene network structure offers a novel platform for exploring innovative 2D thermoelectric materials in research. This study provides crucial theoretical insights to guide the designing and implementation of 2D thermoelectric materials based on fullerenes. [ABSTRACT FROM AUTHOR]

Electronic transport in inversion symmetry broken monolayer phosphorene under the influence of electron–phonon interaction is investigated. Such interaction renormalizes the band structure, leading to a significant modification of electron dynamics, which depends on the interaction strength. We find that the imaginary part of the self-energy remains minimal within a particular region of energy ℏ ω , where the quasiparticle has zero density of final states. It turns out that the emission of phonon is not allowed in that energy range. At the boundary of this region, there is a sudden increase in the imaginary part of the self-energy, where its real part exhibits singular behavior around specific energies. In addition, it is shown that dynamic optical conductivity exhibits remarkable effects in the presence of the electron–phonon interaction. In particular, it remains minimal in a particular region of energy ℏ ω , then it increases monotonically and hits the peak of the main absorption edge. Moreover, we find that the dynamic optical conductivity changes significantly with the change in electron–phonon interaction strength, temperature, phonon energy, chemical potential, and bandgap in the energy spectrum of the system. Both the real and imaginary parts of the self-energy acquire energy dependence that reflects phonon structure and leads to a shift in the conductivity peak of the longitudinal optical conductivity. [ABSTRACT FROM AUTHOR]

Investigating the interplay between charge and spin conversion in two-dimensional (2D) materials holds significant promise for futuristic electronic applications. Through density functional theory, our study delves into the charge-spin conversion and spin density dynamics in the non-magnetic SnNBr monolayer under time-reversal invariance. The breaking of out-of-plane mirror symmetry and inversion symmetry, along with the presence of spin–orbit coupling (SOC) lead to a notable momentum-dependent spin band splitting or Rashba effect induced by the inherent out-of-plane electric field. Theoretical calculations reveal not only the presence of profound Rashba spin splitting but also the coexistence of intrinsic spin Hall effects in the SnNBr monolayer. Analysis of k-resolved spin Berry curvature sheds light on the origin of the substantial intrinsic spin Hall conductivity. Furthermore, our research highlights the modulation of charge-to-spin conversion and spin density accumulation through in-plane biaxial strains. Moreover, the variation in the Rashba parameter is correlated with the changes in the built-in out-of-plane electric field and microscopic atomic orbital contributions. These findings underscore the exceptional potential of the non-centrosymmetric SnNBr monolayer for advanced spintronics, spin-orbitronics, and piezo-spintronic applications, and serve as a catalyst for further experimental investigations. [ABSTRACT FROM AUTHOR]

Cobalt oxides are known for their excellent heat transfer properties. The main component of cobalt oxides is the CoO2 monolayer, which exhibits high-temperature superconductivity caused by strong electron–phonon coupling (EPC). We here systematically investigate the structural stability, electronic structure, and magnetism of the CoO2 monolayer using first-principles and Monte Carlo simulations. On this basis, we further study the changes in the spin energy gap, magnetic axis direction, and other properties of the CoO2 monolayer with the changes in carrier concentration. By appropriately doping the CoO2 monolayer with holes, the magnetic axis direction of the CoO2 monolayer can be reversed, thereby enhancing its potential application in the field of spin electronic devices. Monte Carlo simulation is used to study the regulation of different factors on the magnetothermal properties of the CoO2 monolayer. Through the analysis of physical parameters such as Curie temperature (TC) and bandgap, we find that the appropriate carrier concentration and magnetic field can not only regulate the magnetothermal properties of materials but also further improve the efficiency of materials in low-temperature environments. [ABSTRACT FROM AUTHOR]

Surface-specific sum frequency generation vibrational spectroscopy is applied to study the molecular configuration of short-chain n-alkanethiol self-assembled monolayers (SAMs with n = 2–6) on the Au surface. For monolayers with n ≥ 3, the alkanethiols are upright-oriented, with the CH3 tilt angle varying between ∼33° and ∼46° in clear even–odd dependency. The ethanethiol monolayer (n = 2) is, however, found to exhibit a distinct lying-down configuration with a larger methyl tilt angle (67°–79°) and a smaller CH2 tilt angle (56°–68°). Such a unique configurational transition from n = 2 to n ≥ 3 discloses the steric effect owing to chain–chain interaction among neighboring molecules. Through density functional theory calculations, the transition is further confirmed to be energetically favorable for thiols on a defective reconstructed Au(111) surface but not on the pristine one. Our study highlights the roles of the chain–chain interaction and the substrate surface atomic structure when organizing SAMs, offering a strategic pathway for exploiting their applications. [ABSTRACT FROM AUTHOR]

We report on the observation of longitudinal (in-plane) and transverse (out-of-plane) spin splitting of incident linearly polarized (p and s) light beams reflected at the interface of tungsten di-selenide, a monolayer transition metal dichalcogenide material deposited on a Si/SiO2 substrate, near the Brewster angle of incidence employing the quantum weak measurement technique. The amplified longitudinal and transverse shift values reach up to hundreds of micrometers. The transverse shift value, measured approximately at 400 μm, dominates over the longitudinal shift value at Brewster incidence. In this work, we found positive and negative shift values for the same angle of incidence but distinct polarization states revealing the explicit dependencies upon the angle of incidence and the post-selection angle. The modified weak measurement model provides an excellent interpretation of these experimental findings. This work, thus, provides novel insights into the effects of light–matter interactions and could find important applications in optical switches, nano-photonics, and the non-destructive study of material properties. [ABSTRACT FROM AUTHOR]

Different from the extensive experimental investigations into the thermoelectric (TE) properties of the bulk IV–VI compounds, less attention has been paid to the TE properties of the monolayer IV–VI compounds. Here, we consider the TE transport properties including the Seebeck coefficient, electronic conductance, thermal conductance, power factor, and figure of merit Z T of the undoped and Bi-doped GeS monolayers. Our results show that for both the undoped and Bi-doped monolayers the anisotropy is widely observed in all their TE properties, and the maximum Z T at a certain temperature along the armchair direction is much greater than that along the zigzag direction. Moreover, Bi doping can lead to an increase of the maximum Z T , and there are more Z T peaks appearing near the zero chemical potential. This indicates that the Bi-doped GeS monolayer can work as a TE material at a lower bias voltage, and especially along the armchair direction it can work at zero bias voltage, which obviously strengthens the reliability of the TE devices. As the temperature increases, the maximum Z T will be uniformally increased along the armchair and zigzag directions for both the undoped and Bi-doped GeS monolayers. In the temperature scope from 300 to 800 K, the maximum Z T along the armchair direction of the Bi-doped GeS monolayer will increase from 3.39 to 4.85, which indicates that this Bi-doped GeS monolayer is a promising TE material in a wide-temperature zone. As an application, we have designed the GeS-based TE couples and found that their efficiencies can be greater than 27 % at large temperature differences. This research should be an important guidance for designing a low-voltage, wide-temperature-scope, and high-stability TE device. [ABSTRACT FROM AUTHOR]

Deposition of Mo S 2 on Au(111) alters the electronic properties of Mo S 2 . In this study, we investigate the free-standing MoS 2 monolayer and the MoS 2 /Au(111) heterostructure, with and without strain, as well as defects of interest in memristive and neuromorphic applications. We focus on the so-called atomristor devices based on monolayer materials that achieve resistive switching characteristics with the adsorption and desorption of metal adatoms. Our study confirms that the formation of midgap states is the primary mechanism behind the resistive switching. Our results show that strain lowers the adsorption/desorption energies of Au+defect structures of interest, leading to more favorable switching energies, but simultaneously reduces the switching ratio between states of differing conductivities. The presence of the Au(111) substrate additionally introduces non-uniform amounts of strain and charge transfer to the MoS 2 monolayer. We propose that the induced strain contributes to the experimentally observed n - to p -type transition and Ohmic to Schottky transition in the MoS 2 monolayer. The charge transfer leads to a permanent polarization at the interface, which can be tuned by strain. Our study has important implications on the role of the electrode as being a source of the observed variability in memristive devices and as an additional degree of freedom for tuning the switching characteristics of the memristor device. [ABSTRACT FROM AUTHOR]

We here report the electronic structure calculation of GaInSe3 and GaInTe3 monolayers with the P3m1 (no. 156) space group. The electronic structure and thermoelectric properties of the monolayers are calculated through the Vienna Ab initio Simulation Package and BoltzTraP2 codes. The dynamic and thermodynamic stabilities were verified by calculating their phonon spectra and simulating ab initio molecular dynamics. The monolayers were found to have a direct bandgap, with both PBE + SOC and HSE06 + SOC potentials. The lattice thermal conductivity of GaInTe3 monolayer calculated using Phono3py code shows ultra-low values due to enhanced phonon–phonon scattering. Combining electrical and thermal transport, the values have been evaluated. Importantly, the p-type GaInTe3 has excellent thermoelectric properties at 700 K, with a z T value of 2, indicating that the p-type GaInTe3 has potential application in the field of thermoelectricity. [ABSTRACT FROM AUTHOR]

Electronic relaxation dynamics of solution-phase redox-exfoliated molybdenum disulfide (MoS2) monolayer and multilayer ensembles are described. MoS2 was exfoliated using polyoxometalate (POM) reductants. This process yields a colloidal heterostructure consisting of MoS2 2D sheet multilayers with surface-bound POM complexes. Using two-dimensional electronic spectroscopy, transient bleaching and photoinduced absorption signals were detected at excitation/detection energies of 1.82/1.87 and 1.82/1.80 eV, respectively. Approximate 100-fs bandgap renormalization (BGR) and subsequent defect- and phonon-mediated relaxation on the picosecond timescale were resolved for several MoS2 thicknesses spanning from 1 to 2 L to ∼20 L. BGR rates were independent of sample thickness and slightly slower than observations for chemical vapor deposition-grown MoS2 monolayers. However, defect-mediated relaxation accelerated ∼10-fold with increased sample thicknesses. The relaxation rates increased from 0.33 ± 0.05 to 1.2 ± 0.1 and 3.1 ± 0.4 ps−1 for 1–2 L, 3–4 L, and 20 L fractions. The thicknesses-dependent relaxation rates for POM-MoS2 heterostructures were modeled using a saturating exponential function that showed saturation at thirteen MoS2 layers. The results suggest that the increased POM surface coverage leads to larger defect density in the POM-MoS2 heterostructure. These are the first descriptions of the influence of sample thickness on electronic relaxation rates in solution-phase redox-exfoliated POM-MoS2 heterostructures. Outcomes of this work are expected to impact the development of solution-phase exfoliation of 2D metal-chalcogenide heterostructures. [ABSTRACT FROM AUTHOR]

Owing to the unique asymmetric geometry, Janus monolayer compounds exhibit various exotic thermal properties and have promising applications in thermal management. In this study, we combine machine learning potentials and the phonon Boltzmann transport equation to perform a comparative study of the thermal transport properties in Janus XBAlY (X = Se, S, Te; Y = S, Se, O; X ≠ Y) monolayers. Our findings unveil a thermal conductivity (κ p) ranking as SeBAlS > TeBAlO > SBAlSe, contradicting the conventional expectation that a higher κ p is typically observed when the average atomic mass is smaller. At room temperature, the κ p of SeBAlS is 174 Wm−1 K−1, which is 4.8 times that of SBAlSe when considering three-phonon scattering processes. Moreover, the consideration of four-phonon scatterings does not alter such ranking. The anomalous κ p phenomenon was explained through a detailed analysis of the phonon–phonon scattering mechanism, phonon bandgap, phonon anharmonicity, and chemical bond strength. This study highlights the intricate relationship between atomic mass, bonding characteristics, and thermal properties, offering insights for designing Janus materials with tailored thermal conductivity. [ABSTRACT FROM AUTHOR]

The combined influence of spin–orbit coupling and spatial inversion asymmetry leads to an enhancement of electronic properties, including Rashba spin-splittings as well as spin Hall effect. Recent research has shown the possibility to create two-dimensional Janus materials with inherent structural asymmetry. In this work, the structural stability, piezoelectricity, electronic properties, and intrinsic spin Hall conductivity of quintuple-layer atomic Janus Sb2XSX' (X, X' = S, Se, Te; X ≠ X') monolayers are investigated using first-principles calculations within the framework of density functional theory. They demonstrate relatively high in-plane piezoelectric coefficients ( d 22) and also possess out-of-plane piezoelectric coefficients ( d 31), which is due to the breaking of inversion symmetry in the crystal structure with the space group P3m1. Large Rashba parameters are obtained in Janus Sb2XSX' monolayers, especially high for Sb 2 S 2 Te (1.62 eV Å) and Sb 2 SeSTe (1.33 eV Å) due to strong spin–orbit coupling. Moreover, Rashba-like spin-splitting is also observed in the edge-states as well, which is highest for Sb 2 SeSTe with 2.17 eV Å. Furthermore, Sb 2 S 2 Te and Sb 2 SeSTe monolayers reveal a significantly high Berry curvature (65.59 and 61.05 Bohr 2), spin Berry curvature (− 118.4 and − 120.6 Bohr 2), and spin Hall conductivity (1.8 and 1.6 e 2 /h). Our results suggest that Janus Sb 2 S 2 Te and Sb 2 SeSTe monolayers could be an excellent platform for multifunctional electronic applications. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) piezoelectric nanomaterials have widely been studied recently due to their promise for various applications in technology. Investigation of vertical piezoelectricity will contribute to a deeper understanding of the intrinsic mechanism of piezoelectric effects in the 2D structures. In this paper, we report a first-principle study for the structural, electronic, piezoelectric, and transport properties of new-designed Janus WSi Z 3 H (Z = N, P, and As) monolayers. The structural stability of WSi Z 3 H is theoretically confirmed based on the energetic, phonon dispersion, and also elastic analyses. At the ground state, while WSiN 3 H is an indirect semiconductor, both WSiP 3 H and WSiAs 3 H are predicted to be direct semiconductors with smaller bandgaps. When the spin-orbit coupling effects are taken into account, a large valley spin splitting is observed at the K point of WSi Z 3 H materials. Interestingly, a giant Rashba spin splitting is found in WSiP 3 H and WSiAs 3 H with Rashba constant α R up to 770.91 meV Å. Additionally, our first-principles study indicates that Janus WSi Z 3 H monolayers are piezoelectric semiconductors with high out-of-plane piezoelectric coefficient | d 31 | , up to 0.15 pm/V, due to the broken mirror symmetry. Besides, with high electron mobilities and also possessing direct band gaps, WSiP 3 H and WSiAs 3 H monolayers are favorable for applications in optoelectronics. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) intrinsic ferromagnetic (FM) materials are promising candidates for fabricating next generation high-performance spintronic devices. However, all experimentally verified 2D FM semiconductors have Curie temperature (Tc) far below room temperature, which hinders their practical applications. Based on first-principles calculations, a stable and previously undiscovered 2D CrGaS3 structure is predicted, which is a semiconductor with an indirect bandgap of 1.99 eV and displays out-of-plane magnetic anisotropy. More importantly, it exhibits high-temperature ferromagnetism, with Tc ranging between 520 and 814 K. The high Tc is attributed to the presence of both direct-exchange and super-exchange interactions that are ferromagnetic, along with the eg-px/py-eg super exchange having a zero virtual exchange gap. Furthermore, it has been observed that the magnetic anisotropy can be tuned by external strain. These findings indicate its potential as a promising candidate for the rapid development of 2D spintronic applications. [ABSTRACT FROM AUTHOR]

Polymers are known to wet nanopores with high surface energy through an atomically thin precursor film followed by slower capillary filling. We present here light interference spectroscopy using a mesoporous membrane-based chip that allows us to observe the dynamics of these phenomena in situ down to the sub-nanometer scale at milli- to microsecond temporal resolution. The device consists of a mesoporous silicon film (average pore size 6 nm) with an integrated photonic crystal, which permits to simultaneously measure the phase shift of thin film interference and the resonance of the photonic crystal upon imbibition. For a styrene dimer, we find a flat fluid front without a precursor film, while the pentamer forms an expanding molecular thin film moving in front of the menisci of the capillary filling. These different behaviors are attributed to a significantly faster pore-surface diffusion compared to the imbibition dynamics for the pentamer and vice versa for the dimer. In addition, both oligomers exhibit anomalously slow imbibition dynamics, which could be explained by apparent viscosities of six and eleven times the bulk value, respectively. However, a more consistent description of the dynamics is achieved by a constriction model that emphasizes the increasing importance of local undulations in the pore radius with the molecular size and includes a sub-nanometer hydrodynamic dead, immobile zone at the pore wall but otherwise uses bulk fluid parameters. Overall, our study illustrates that interferometric, opto-fluidic experiments with mesoporous media allow for a remarkably detailed exploration of the nano-rheology of polymeric liquids. [ABSTRACT FROM AUTHOR]

For the most precise incorporation of single impurities in silicon, which is utilized to create quantum devices, a monolayer of adatoms on the Si(100) surface and a dopant-containing molecule are used. Here, we studied the interaction of phosphorus tribromide with a chlorine monolayer with mono- and bivacancies using a scanning tunneling microscope (STM) at 77 K. The combination of different halogens in the molecule and the adsorbate layer enabled unambiguous identification of the structures after PBr3 dissociation on Si(100)-Cl. A Cl monolayer was exposed to PBr3 in the STM chamber, which allows us to compare the same surface areas before and after PBr3 adsorption. As a result of this comparison, we detected small changes in the chlorine layer and unraveled the molecular fragments filling mono- and bivacancies. Using density functional theory, we found that the phosphorus atom occupies a bridge position after dissociation of the PBr3 molecule, which primarily bonds with silicon in Cl bivacancies. These findings provide insight into the interaction of a dopant-containing molecule with an adsorbate monolayer on Si(100) and can be applied to improve the process of single impurity incorporation into silicon. [ABSTRACT FROM AUTHOR]

AgCrS e 2 exhibits remarkably high ionic conduction, an inversion symmetry-breaking structural transition, and is host to complex non-colinear magnetic orders. Despite its attractive physical and chemical properties and its potential for technological applications, studies of this compound to date are focused almost exclusively on bulk samples. Here, we report the growth of AgCrS e 2 thin films via molecular beam epitaxy. Single-orientated epitaxial growth was confirmed by x-ray diffraction, while resonant photoemission spectroscopy measurements indicate a consistent electronic structure as compared to bulk single crystals. We further demonstrate significant flexibility of the grain morphology and cation stoichiometry of this compound via control of the growth parameters, paving the way for the targeted engineering of the electronic and chemical properties of AgCrS e 2 in thin-film form. [ABSTRACT FROM AUTHOR]

By using first-principles calculations and micromagnetic simulations, we investigate the electronic structure, magnetic properties, and skyrmions in two-dimensional Janus Cr 2 XYTe 6 (X,Y = Si, Ge, Sn, X ≠ Y) monolayers. Our findings reveal that the Cr 2 XYTe 6 monolayers are ferromagnetic semiconductors with a high Curie temperature (T c). The bandgap and T c can be further increased by applying tensile strain. In addition, there is a transition from the ferromagnetic to the antiferromagnetic state at a compressive strain. Both Cr 2 SiSnTe 6 and Cr 2 SiGeTe 6 exhibit a large magnetic anisotropy energy, which are mainly associated with the significant spin–orbit coupling of the nonmagnetic Te atoms rather than that of the magnetic Cr atoms. Interestingly, the Cr 2 SiSnTe 6 monolayer exhibits a significant Dzyaloshinskii–Moriya interaction of 1.12 meV, which facilitates the formation of chiral domain walls and skyrmions. Furthermore, under tensile strain, chiral DWs can be transformed into skyrmions if applying an external magnetic field. These findings suggest that Janus Cr 2 XYTe 6 monolayers hold promise for spintronic nanodevice applications. [ABSTRACT FROM AUTHOR]

We have developed an experimental and analytical setup for thermal desorption spectroscopy of solid water films on surfaces. We obtain the coverage-dependent desorption kinetics of water molecules from a well-defined ultra-thin alumina/NiAl(110) surface in the coverage range of 0–2 monolayers. We use a novel deconvolution technique to eliminate the pumping delay of water vapor in the vacuum system, which has previously hindered the accurate estimation of desorption kinetic parameters, such as activation energy and pre-exponential factor. The coverage-dependent Arrhenius analysis reveals that the desorption activation energy decreases with increasing coverage in the sub-monolayer range, indicating that the water–water interaction is not attractive. We also find that the pre-exponential factor for the second layer is higher than that for the sub-monolayer. We explain this difference in terms of transition state theory and propose that entropic effects play a significant role in water desorption kinetics. [ABSTRACT FROM AUTHOR]

In this work, we calculated the lattice thermal conductivity of monolayer InTe by means of phonon Boltzmann transport theory with first-principles calculated inter-atomic force constants. The higher-order phonon anharmonicity was found to play a strong impact on thermal transport in InTe. With the involvement of the phonon–phonon scattering process up to the fourth-order, the in-plane lattice thermal conductivity of monolayer InTe is 5.1 W m−1 K−1 at room temperature, which is 35% of that considering only third-order force constants. Furthermore, strain was found to be an effective way to manipulate the thermal transport in InTe, which reduces to one half when applying 5% in-plane tensile strain. The strain adjustment is due to the decreases in the phonon group velocity as well as the increase in the phonon scattering rates. These findings can enrich thermal transport properties of group-III monochalcogenides and benefit the material design of thermoelectrics and thermal management electronic devices. [ABSTRACT FROM AUTHOR]

In this paper, we examined the effects of proximity-induced interactions such as Rashba spin-orbit coupling and effective Zeeman fields (EZFs) on the optical spectrum of n -type and p -type monolayer (ML)-MoS 2. The optical conductivity is evaluated using the standard Kubo formula under random-phase approximation by including the effective electron–electron interaction. It has been found that there exist two absorption peaks in n -type ML-MoS 2 and two knife shaped absorptions in p -type ML-MoS 2 , which are contributed by the inter-subband spin-flip electronic transitions within conduction and valence bands at valleys K and K ′ with a lifted valley degeneracy. The optical absorptions in n -type and p -type ML-MoS 2 occur in THz and infrared radiation regimes and the position, height, and shape of them can be effectively tuned by Rashba parameter, EZF parameters, and carrier density. The interesting theoretical predictions in this study would be helpful for the experimental observation of the optical absorption in infrared to THz bandwidths contributed by inter-subband spin-flip electronic transitions in a lifted valley degeneracy monolayer transition metal dichalcogenides system. The obtained results indicate that ML-MoS 2 with the platform of proximity interactions make it a promising infrared and THz material for optics and optoelectronics. [ABSTRACT FROM AUTHOR]

Two-dimensional molybdenum disulfide (MoS2) has been proved to be a good candidate in photodetectors, and MoS2/graphene (MoS2/G) heterostructure has been widely used to expand the optical response wavelength of MoS2. To clarify the carrier transfer dynamics in the MoS2/G heterostructure, time-resolved transient absorption and two-color pump–probe measurements are performed. By comparing the carrier dynamics in MoS2 and MoS2/G under different pump wavelengths, we find that interfacial excitons are formed in the heterostructure, and fast hot carriers transfer (<200 fs) from graphene to MoS2 are observed. The results indicate that the formed heterostructure with graphene can not only expand the optical response wavelength of MoS2 but also improve the response time of the device in the near-infrared region. [ABSTRACT FROM AUTHOR]

Controlled shrinkage of hydrothermal carbon coating (HTCC) during its carbonization preparation process offers a novel strategy for optimizing the interfacial properties of fiber-reinforced ceramic matrix materials. In this study, the effect of volumetric shrinkage in monolayer or bilayer HTCC on the interface characteristics and mechanical properties of C f /ZrB 2 -SiC composites is investigated. The bilayer HTCC significantly enhances the crack deflection effect within the interphase compared to the monolayer HTCC. By precisely controlling the shrinkage of the layers of the bilayer HTCC, an innovative C/SiC/C trilayer interphase was synthesized in situ during the polymer infiltration process for preparing the C f /ZrB 2 -SiC composites, which synergistically enhances stress dispersion and load transfer efficiency within the interface. The work of fracture for C f /ZrB 2 -SiC composites modified by the trilayer interphase has been significantly elevated to 2258 J/m2, which far exceeds the 129 J/m2 measured for the composites lacking a HTCC interphase. [ABSTRACT FROM AUTHOR]

This letter reports a time resolved pump-probe reflectance spectroscopic study on moiré excitons in a twisted monolayer WS2/WSe2 heterostructure. By probing at the resonant energies of intralayer excitons, we observed their distinct temporal tracks under the influence of interlayer excitons, which we attribute to the discrepancy in spatial distribution of the intralayer excitons in different layers. We also observed that intralayer moiré excitons in WSe2 layer differ at decay rate, which reflects different locations of Wannier-like and charge-transfer intralayer excitons in a moiré cell. We concluded that the interlayer moiré excitons form within a few picoseconds and have the lifetime exceeding five nanoseconds. Our results provide insights into the nature of moiré excitons and the strain's significant impact on their behaviour in twisted heterostructures, which could have important implications for the development of novel optoelectronic devices. [ABSTRACT FROM AUTHOR]

The development of sustainable synthetic methods for converting alcohols to amines is of great interest due to their widespread use in pharmaceuticals and fine chemicals. In this work, we present an electrochemical approach by using green electrons for the selective oxidation of benzyl alcohol to benzaldehyde using a NiOOH catalyst, followed by its reductive amination to form benzyl-tert-butylamine. The number of Ni monolayer equivalents on the catalyst was found to significantly influence selectivity, with 2 monolayers achieving up to 90% faradaic efficiency (FE) for benzaldehyde in NaOH, while 10 monolayers performed best in a tert-butylamine solution (pH 11), yielding 100% FE for benzaldehyde. Reductive amination of benzaldehyde was optimized on Ag and Pb electrodes, with Ag achieving 39% FE towards the amine product, though hydrogen evolution remained a competing reaction. In situ FTIR spectroscopy confirmed the formation of benzaldehyde and its corresponding imine intermediate during oxidation, while reduction spectra supported the formation of the amine product. These results demonstrate the potential of paired electrolysis for alcohol-to-amine conversion, achieving an overall 35% FE for the synthesis of benzyl-tert-butylamine. This work paves the way for more efficient and sustainable electrochemical routes to amine synthesis. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) monolayers have gained significant attention as ultrathin active layers for fabricating atomic-scale memristor (atomristor) structures due to their crystalline structures and clean surfaces. This study reports on the giant memory window performance and low power consumption of the atomristor structures using a hexagonal boron nitride (h-BN) monolayer and symmetric silver (Ag) metal electrodes through a polypropylene carbonate (PPC) assisted transfer method. The h-BN atomristor exhibits the highest memory window (~4 × 109), the lowest leakage current (~0.24 pA), and the lowest power consumption (~3 × 10−14 W) compared to the other 2D atomristors. Furthermore, the h-BN atomristor achieves significant endurances and yields of up to 10,000 switching cycles and 77%, respectively, due to the superior thermomechanical properties of the PPC support layer for transferring ultrathin and large-area h-BN monolayers. These results represent a significant step toward the realization of high-performance and energy-efficient neuromorphic computing circuits based on 2D monolayers. [ABSTRACT FROM AUTHOR]

Self‐healing polyvinyl alcohol‐polyacrylic acid (PVA‐PAA) composite films incorporated with molecular iodine (I2) are presented for optoelectronic applications. The incorporation mechanism between the PVA‐PAA donor and I2 acceptor is investigated by studying the chemical, crystal, and morphological properties of the composite films. Incorporating PVA‐PAA composite films with I2 decreases the crystallinity degree of the composite films, which increases the electrical conductivity by enabling the segmental motion in the polymer matrix. PVA‐PAA/I2 composite films are stable at temperatures lower than 200°C, where the majority of optical, optoelectronic, and electrical applications can be realized. Additionally, introducing I2 into the PVA‐PAA matrix increases the melting temperature of the composite films. Moreover, the optical and electrical properties of the PVA‐PAA/I2 composite films are investigated. The bandgap energy of PVA‐PAA film is 3.88 eV, decreasing continuously to 3.38 eV as I2 concentration increases to 16 wt.%. On the other hand, The average conductivity of the PVA‐PAA film is 7.46×10−6S×cm−1. Increasing I2 concentration in the PVA‐PAA matrix increases the electrical conductivity continuously up to 1.33×10−4S×cm−1. The physical properties of the PVA‐PAA/I2 composite films exhibit self‐healing properties after thermal treatment and UV irradiation that occur during the operation cycling in optical, optoelectronic, and electrical applications. [ABSTRACT FROM AUTHOR]

In the present work, with the aid of the density functional theory (DFT) method, we have investigated the possibility of applying the B3S monolayer (B3SML) for sensing and adsorption of some air pollutants containing SO2, CS2, CO2, CH2O, H2O, C2H2, and CF3H from the gaseous environment. The results showed that after the adsorption of SO2, H2O, and C2H2 by B3SML, big changes took place which led to a decrease of the λmax of each complex down to 1598.5 nm, 1418.0 nm, and 1580.0 nm, respectively. Therefore, the frequencies of the mentioned adsorption complexes rise and strong blueshifts occur. Moreover, the outcomes of the band gap estimations reveal that the B3SML could selectively detect the existence of C2H2 with a clearer and stronger electronic signal compared to all other gases. In addition, this nanosheet is able to sense CS2, CH2O, SO2, and H2O with good signals. Hence, it could not recognize the difference between CH2O and SO2 gases. Also, the results of the thermodynamic calculations indicate that B3SML would selectively adsorb and destruct SO2, C2H2, and H2O gases. Moreover, this sorbent could adsorb CH2O and CS2 species, but it would approximately not adsorb CO2 and CF3H. [ABSTRACT FROM AUTHOR]

The adsorption of Th(IV) ions by nano-Kaolin and nano-Kaolin/MnFe2O4 composite were studied as a function of pH, sorbent mass, time, and temperature. Kinetic data was fitted to pseudo second-order model, and the maximum value of the adsorption capacity of the monolayer (qm) for nano-Kaolin and nano-Kaolin/MnFe2O4 was at pH 3. The Langmuir, Freundlich, and Dubinin–Radushkevich isotherm equations were fitted to the adsorption data and the proper constants were calculated. From adsorption isotherms at different temperatures, ΔH° (endothermic), ΔG° (favourable), and ΔS° (positive) were calculated. [ABSTRACT FROM AUTHOR]

Pt/α-MoC1-x catalysts exhibit exceptional activity in low-temperature water-gas shift reactions. However, quantitatively identifying and fine-tuning the active sites has remained a significant challenge. In this study, we reveal that fully exposed monolayer Pt nanoclusters on molybdenum carbides demonstrate mass activity that exceeds that of bulk molybdenum carbide catalysts by one to two orders of magnitude at 100–200 °C for low-temperature water-gas shift reactions. This advancement is driven by the precise quantification and elucidation of active sites along the Pt-molybdenum carbide interfacial perimeter. By combining sacrificial CO adsorption per Pt atom, Density Functional Theory calculations, and CO chemisorption measurements, we establish a direct correlation between the monolayer Pt nanocluster size and the number of interfacial perimeters on Pt/α-MoC1-x catalysts. In this work, these findings provide key insights into the active site configuration of Pt/α-MoC1-x catalysts and open pathways for innovative catalyst design, with the interfacial perimeter identified as a crucial factor in enhancing catalytic performance. A direct correlation between the monolayer Pt nanocluster size and the number of interfacial perimeters on Pt/α-MoC1-x catalysts was established by combining sacrificial CO adsorption per Pt atom, DFT calculations, and CO chemisorption measurements. [ABSTRACT FROM AUTHOR]

Multilayer flakes of two-dimensional materials were recently shown to be tunable by twisting monolayers on their surface. This raises the question whether qualitatively new phenomena can occur in such finite-thickness moiré systems. Here we demonstrate the emergence of distinct topological phases and transitions in N-layered flakes of nodal superconductors with a single monolayer twisted on top of it. We show that a c-axis current transforms the whole system into a chiral topological superconductor. Increasing the current drives a sequence of topological transitions between states characterized by a Chern number increasing from ~ O (N) up to ~ O ( N 2 ) , well beyond the additive effect of stacking N layers. We predict thickness-independent signatures of these states in the thermal Hall and tunneling microscopy measurements. Twisted superconductor flakes thus provide an example of a "2.5-dimensional" material where the synergy of two-dimensional layers extended in a third dimension realize states inaccessible in either monolayer or bulk materials. [ABSTRACT FROM AUTHOR]

AbstractLimiting animal experiments is essential for ethical issues and also because scientific evidence highlights the discrepancies between human and animal metabolism. This review aims to provide a critical discussion of the strengths and limitations of the most appropriate in vitro intestine model to answer complex research questions in pharmaceutical and nutraceutical fields. This review describes the components contributing to the definition of the gut barrier structure, from the outer mucus layer to the inner part of lamina propria, including endothelial and neuronal networks. We conclude that the main advantage of these co-culture models is their versatility since they are modulable systems in which each component can be added, changed, or removed to reproduce a specific physiological condition each time. Additionally, we compare intestinal organoid models and microfluidic systems with well-established co-culture models. [ABSTRACT FROM AUTHOR]