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[Display omitted] • Shock response of lightweight multicomponent alloy is simulated by AIMD with MSST. • Both migration of atoms and electronic transition are involved in shock compression. • Multicomponent alloy can be disordered due to different migration ability of atoms. • Crystal orbitals contributions and density of states are changed after compression. • Electrons response more quickly to the shock compression than crystal structure. The dynamic response of shock wave impact on single crystal aluminium and lightweight multicomponent alloy Al-Cu-Li-Mg is simulated by using the combination of Ab initio Molecular Dynamics (AIMD) and Multi-Scale Shock Technique (MSST), with the analysis carried out at the atomic/electronic levels. The simulation is verified by comparing the particle velocity of single crystal obtained in this work with the data in literature. The shock compression process not only involves the migration of atoms, but also is related to electronic transition. Two stages could be found in the shock compression process: oscillatory compression of the crystal cell and oscillatory migration of the atoms. The crystal structure of the multicomponent alloy could be disordered even at low shock speed, due to the difference in the ability to migrate between different kinds of atoms. As the sample is shock-compressed, the contribution proportion of crystal orbitals shows a sharp decrease for D orbital, while it increases significantly for S orbital and P orbital. The electron structure shows a quicker response to the shock wave compression process than the crystal structure. The orbital contribution from P orbital of the crystal is mainly due to the P orbital of Al atoms, while the orbital contribution from D orbital of the crystal is mainly due to the D orbital of Cu atoms. Total Density of States (TDOS) is mainly contributed by the Projected Density of State (PDOS) of Cu atoms in the occupied state of energy levels, while it is close to the PDOS of Al atoms in the non-occupied state of energy levels. [ABSTRACT FROM AUTHOR]

[Display omitted] • The adsorption of PH 3 on perfect Zr 2 CO 2 was physical adsorption. • The introduction of O-vacancy enhanced the adsorption stability of the PH 3 molecule. • The doping of transition-metal significantly improved the sensitivity of Zr 2 CO 2 toward PH 3 gas. • O-vacancy defected, Co– and Ru-doped Zr 2 CO 2 have great potential as sensors toward PH 3. • Fe- and Rh-doped Zr 2 CO 2 can be used as adsorbents to effectively remove PH 3 gases. In this study, the potential application of the Zr 2 CO 2 -MXene structures as PH 3 sensors and adsorbents for industrial or living applications was investigated using the first-principles approach of density functional theory (DFT). The adsorption of PH 3 on pristine, O-defected, and transition metal (TM; such as Cr, Mn, Fe, Co, Y, Mo, Ru, Rh)-doped Zr 2 CO 2 structures was explored. The results showed that the introduction of TM dopant improved the Zr 2 CO 2 activity more than the O-vacancy. The large adsorption energy, short interaction distance, and high charge transfer suggested chemisorption of PH 3 molecules on TM-doped Zr 2 CO 2. After the PH 3 molecule was adsorbed, the band gap of Zr 2 CO 2 with O-vacancies, Co-doped Zr 2 CO 2 , and Ru-doped Zr 2 CO 2 decreased by 0.132 eV, and increased by 0.065 eV, 0.073 eV, respectively. The changes in band gap generated an electrical signal that were used for PH 3 detection; thus, Zr 2 CO 2 with O-vacancies and Co– and Ru-doped Zr 2 CO 2 can be used as effective PH 3 sensors because of their high sensitivity. Fe- and Rh-doped Zr 2 CO 2 also showed promising function as adsorbents for PH 3 gas molecules because of their high adsorption stabilities and long recovery times. After adsorption of six PH 3 molecules, their adsorption energies on Fe- and Rh-doped Zr 2 CO 2 were −1.142 eV and −1.135 eV, with recovery times of 1.49 × 107 s and 1.12 × 107 s, respectively. The findings of this study offer novel insights for the development of MXene-based sensors and adsorbents. [ABSTRACT FROM AUTHOR]

Semiconducting half-Heusler alloys are potential candidates for thermoelectric generators operational at high temperatures. In this work, the stability, electronic, and thermoelectric properties of 18 valence electron TiXPb (X = Ni, Pd, Pt) compounds are investigated using density functional theory and semi-classical Boltzmann transport theory. The compounds are both thermodynamically and dynamically stable. We find them to be semiconductors with indirect band gaps lying between 0.32−0.64 eV. Our calculations show that from thermoelectric performance perspective electrons exhibit better transport properties than holes. A combination of large power factor and low lattice thermal conductivity results in z T > 1 in all the materials. Our calculations predict that amongst the three compounds, TiPtPb have a maximum value of z T for both electrons and holes. In this material our calculation yields a maximum z T of 2.22 at 900 K for n-type doping at a doping concentration of 9.46 × 1 0 20 cm − 3 and 1.80 at 900 K for p-type doping at a doping concentration of 4.51 × 1 0 20 cm − 3. [Display omitted] • TiXPb (X = Ni, Pd, Pt) half Heuslers are studied for thermoelectric applications. • All these are found to be thermodynamically, mechanically and dynamically stable. • TiPtPb have the lowest value of lattice thermal conductivity 3.46 Wm − 1 K − 1 . • Combination of high power factor and low lattice thermal conductivity results in z T > 1. • TiPtPb with z T ≃ 2. 22 (1.80) for electrons (holes) at 900 K shows best performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • We have calculated the electronic structure, thermal conductivity, and thermoelectric properties of a novel 2D NbOX 2 (X=Cl, Br, I) materials. • The increase in atomic number leads to a curved flat-band structure, accompanied by an enhancement in the power factor and a reduction in thermal conductivity. • The unique structure of monolayer NbOX 2 induces an anisotropy thermoelectric properties, characterized by superior electrical transport properties along the x direction and lower thermal conductivity along the y direction. • The n -type and p -type ZT values of NbOI 2 in the x direction at 300 K(500 K) are 2.91(3.96) and 2.12(3.20), respectively, indicating the promising application potential of NbOI 2 in the field of thermoelectric. In recent years, there has been increasing interest in two-dimensional (2D) thermoelectric materials owing to their potential to achieve enhanced thermoelectric conversion efficiency, driven by quantum size effects. Here, we employed density functional theory (DFT) to investigate the thermoelectric and mechanisms properties of a novel monolayer NbOX 2 (X=Cl, Br, I). We identified a broad and flat band below the Fermi level, mainly contributed by the d z 2 orbitals of the niobium atoms. This flat band will result in a relatively large effective mass (m *) and manifests as a peak in the density of states (DOS), known as a Van Hove singularity. Notably, the monolayer NbOX 2 exhibits outstanding electronic transport properties along the x -direction and demonstrates reduced lattice thermal conductivity (κ l) along the y -direction. The anisotropic κ l of monolayer NbOI 2 is measured at only 0.76 (0.45) W/m/K along the x (y) direction at room temperature, potentially attributed to strong nonharmonic interaction. Moreover, as the atomic number of the halogen elements increases, it leads to an enhancement of the power factor and a reduction in κ l. At 300 K, the maximum anisotropic ZT values with n -type and p -type for NbOI 2 in the x (y) direction are recorded at 2.91 (0.87) and 2.12 (0.97), respectively. When the temperature rises to 500 K, its p (n)-type ZT in the x direction can attain values as high as 3.96 (3.20), indicating that the NbOI 2 has good application potential in the realm of thermoelectrics. [ABSTRACT FROM AUTHOR]

Theoretical investigation of hydrogenation processes has applied to magnesium diborides under ambient conditions, which identified two structurally stable phases, i.e, Mg 4 B 6 H 2 and Mg 4 B 4 H 4. These identifications were evaluated through assessments of their lattice dynamics stability using density functional perturbation theory. Both phases exhibit metallic behavior within their electronic band structures. Our findings showcase the significant impact of anisotropic Migdal–Eliashberg calculations, enhancing the superconducting properties within this system and resulting in a notably higher T c of 34 K. Mg 4 B 4 H 4 exhibits superconductivity with a T c of 17 K under atmospheric conditions, as determined by anisotropic Migdal–Eliashberg calculations. Our study underscores the wide range of structural variations achievable through the hydrogenation of MgB 2 and highlights the crucial importance of hydrogen atom placement within these structures. In addition, the calculation result indicates the influence of band dispersion characteristics on Fermi velocity, a factor attributed to both anharmonicity and harmonicity, which plays a pivotal role in determining the superconducting properties of these materials. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] The diffusion of Co and Ga atoms in α-Ti has been studied using the projector augmented-wave method in combination with the transition state theory. The formation energies of the interstitial and substitutional defects and the corresponding migration and activation energies along two crystallographic directions within the interstitial and vacancy diffusion mechanisms have been calculated. It has been shown that the energetically preferred interstice for the incorporation of both impurities is crowdion. In the case of Co, the formation energy of this defect is only 0.7 eV higher than that of the substitutional defect, while for Ga this difference reaches 2.6 eV. Using the Landman method and the eight-frequency model, the diffusion coefficients of Co and Ga have been calculated within both interstitial and vacancy mechanisms. It has been shown that Co diffusion occurs faster through the interstitials, while Ga diffuses within the vacancy mechanism. The migration and activation energies as well as diffusion coefficients and their anisotropy obtained in these cases are consistent with experimental data. [ABSTRACT FROM AUTHOR]

[Display omitted] The quest for efficient and sustainable energy solutions has led to the exploration of novel materials for photovoltaic cells (PVC). Copper chalcogenides, particularly Cu 2 ZnSnS 4 (CZTS), have emerged as promising candidates due to their abundance and low toxicity. However, CZTS suffers from efficiency limitations attributed to crystal quality and structural instability. Substitutional alloying offers a pathway to enhance CZTS properties, yet challenges persist in achieving significant efficiency gains. This study investigates the substitutional effect of titanium (Ti) in CZTS through ab initio calculations using the generalized gradient approximation plus Hubbard U correction (GGA+ U). Specifically, Ti is substituted at various concentrations in Sn sites to explore its impact on electronic and optical properties. The study employs density functional theory (DFT) calculations to elucidate the structural, electronic and optical characteristics of Ti-substituted CZTS alloys. Notably, the inclusion of effective spin–orbit coupling (SOC) within the GGA+ U framework enhances the accuracy of band gap predictions. Results reveal that Ti substitution enlarges the band gap, thereby improving the absorption coefficient spectrum, indicative of potential applications in enhancing CZTS PVC efficiency. Overall, this work underscores the importance of alloying strategies in tailoring the functional properties of CZTS for advanced PVC applications. [ABSTRACT FROM AUTHOR]

The investigation of defect properties in silicon, including charge transition levels and non-radiative carrier capture, has been ongoing for over 60 years. However, many questions still lack a complete understanding. Bistable defects are of particular interest due to their ability to have different atomic configurations. Our focus is on the bistable trivacancy in silicon. This study reports on the atomic configurations, formation energies, charge transition levels, and carrier capture cross-sections. The results were obtained through first-principles density-functional calculations using a hybrid exchange–correlation energy functional. To calculate capture cross-sections, a one-dimensional approximation is used for the configurational coordinate diagrams, taking into account anharmonicity and a static approximation for calculating the matrix elements of electron–phonon interaction. The resulting atomic structures and charge transition levels are in excellent agreement with previous experimental and theoretical studies. The obtained hole capture cross-sections by donor levels agree with experimental apparent values. The electron capture cross-sections are approximately two orders of magnitude lower than experimental values. This discrepancy can be explained by the use of the one-dimensional approximation. The cross-section values obtained made it possible to estimate the generation current at T = 300 K and to demonstrate that the acceptor level ɛ (0 / 1 −) of the "part of the hexagonal ring" (PHR) configuration is the effective recombination center responsible for the generation current in the reverse biased silicon diode under irradiation. • The stable configuration of a trivacancy is the FFC structure in the neutral charge. • The calculated hole capture cross-sections are in agreement with experimental data. • The calculated electron-capture cross sections are underestimated. • The calculated capture-sections allow estimation of the generation current. [ABSTRACT FROM AUTHOR]

The mechanical and magnetic properties of three equiatomic (FeTiVNi, FeCoVNi, and FeTiGeCo), and two non-equiatomic (FeTiGe 0.75 Se 0.25 Co and FeTiGe 0.5 Se 0.5 Co) high entropy alloys (HEAs) were considered by density functional theory. The results show that when Ti is replaced with Co in the FeTiVNi high entropy alloy, its structure transforms from body-centred cubic into face-centred cubic. On the other hand, when V and Ni are replaced by Ge and Ti in the FeCoVNi alloy, the structure of FeTiGeCo alloy remains body-centred cubic. The formation energy and phonon dispersion results show that the considered high entropy alloys are thermodynamically and dynamically stable. Their elastic constants satisfy Born's stability condition, indicating their mechanical stability. Since FeTiGeCo alloy only marginally meets this stability condition, we also investigated its Se-doped structures, FeTiGe 0.75 Se 0.25 Co and FeTiGe 0.5 Se 0.5 Co, both of which are found to be mechanically stable. Poisson's and Pugh's ratios imply that all the considered high entropy alloys are ductile. Analysis of the electronic structure from the density of states and band structure reveals that these alloys have a metallic character. The highest magnetic moment per atom of 18.752 μ B was obtained for FeCoVNi, with main contributions from Fe and Co atoms. Due to their high magnetic moments, considered high entropy alloys may have potential applications as magnetic materials in power electronics. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Studied the adsorption of SMR intermediates on Ni 4 /CeO 2 , finding active sites were not limited to the metal sites. • By calculating different reaction paths, Ni 4 modification changed the rate-limiting step and improved the reaction efficiency. • The interaction of Ni 4 cluster and CeO 2 surface reduced reaction energy of methane activation and water dissociation. • The electronic structure analysis illustrates the reason why the modified surface promotes SMR and changes the rate-limiting step. Steam methane reforming was an efficient means to produce syngas from natural gas. The electronic structure of Ni 4 clusters modified CeO 2 catalysts would change, and this could promote the reaction. The study investigated methane steam reforming over Ni clusters adsorbed on CeO 2 (1 1 1) using the density functional theory (DFT + U) method. The most stable model configurations were obtained by placing Ni 4 clusters in the top, bridge, and hollow sites on the CeO 2 (1 1 1) surface O. The results indicate that the most stable adsorption model is the adsorption of Ni 4 clusters on the surface O. On this basis, the free energies were calculated by frequency calculation for each steadied adsorption configuration, and the primary reaction pathways of steam methane reforming were discovered comparing changes of free energies about each pathway. Main research achievements were as follows: Steam methane reforming comprised four steps of CH 4 direct dissociation, H 2 O dissociation, CO/H 2 formation and the reaction of intermediates. Furthermore, the catalytic property of Ni 4 clusters modified CeO 2 catalysts was greater than CeO 2 surface. This study reveals the complete reaction pathway of methane steam reforming on nickel-cerium-based materials, which is useful for the development and improvement of methane steam reforming catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] The Fe–Co–Ni ternary system has garnered considerable research interest owing to its distinctive physical and chemical properties. This study investigates the physical quantities related to the magnetic transition temperature, magnetization, and phase occupancy of the Fe–Co–Ni ternary system using coherent potential approximation (CPA), a first-principles computational approach. The CPA results were combined with deep learning techniques to comprehensively understand the magnetic transition temperature, phase stability, and temperature-dependent magnetization of the system. These findings offer new insights into the magnetic properties and phase stability of the Fe–Co–Ni ternary system. [ABSTRACT FROM AUTHOR]

The present work aims to investigate the effects of meta-GGA functionals on the structural, optoelectronic and thermoelectric properties of LiXY(X=Be, Mg, Zn, Cd and Y=N, P, As, Sb, Bi) half-Heusler alloys using density functional theory (DFT) and classical Boltzmann transport theory. The obtained lattice constants of these alloys are in good agreement with the experimental values, exhibiting a slight decrease slightly with meta-GGA functionals compared with GGA-PBE. Band structure calculations demonstrate that the materials exhibit semiconductor character and provide validation for the use of meta-GGA functionals, particularly the r2SCAN and rSCAN, to predict the band gap values of LiXY more accurately. Optical and thermoelectric properties are calculated and discussed in detail. The results reveal that the meta-GGA functionals predict a significant change compared with GGA-PBE in the low energy and temperature region, while in the high energy and temperature regions, all four functionals present almost the same change trends. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] Phosphorene is a two-dimensional (2D) semiconductor material that has attracted a lot of interest in several fields of applications. The anisotropic character of this new category of materials allows the tunability of electrical, optical, thermal, and other properties by the application of fields or forces. In the present work, using density functional theory (DFT) with the hybrid functional and Boltzmann transport equation, electronic properties, phonon dispersion and thermoelectric properties were calculated for AB bilayer phosphorene. To study the effect of the layer deformation on the thermoelectric properties of phosphorene, uniaxial tensile and compressive strain along the armchair and the zigzag direction was applied. The results revealed that AB bilayer phosphorene under a uniaxial tensile strain of 3 % along the armchair direction improve the thermoelectric properties, giving rise to a significant increase of the figure of merit to ZT = 1.24 at n-type doping. The increase of ZT upon uniaxial deformation corresponds to an increase of 110 % with respect to ZT of the unstrained AB bilayer phosphorene structure (ZT = 0.59 at 300 K). [ABSTRACT FROM AUTHOR]

The electronic and magnetic properties of KCaN 2 /KCl(001) heterojunction have been studied within the framework of density functional theory using the full-potential linear augmented plane waves plus local orbital approach. There are two possible interface layers depending on the crystal structure of KCaN 2. The results demonstrate that the half-metallicity nature remains in both possible interfaces, i.e., KCl/KCa and KCl/NN. Spin polarization in both interfaces is complete, % 100, and the interface effects do not affect half-metallicity. The Schottky barrier height, band offsets, valence band maximum, and conduction band minimum to these interfaces were calculated and compared with the other half-metal/semiconductor heterostructures. • Half-metallicity preserves at the both KCl/KCa and KCl/NN interfaces. • There are two types of band alignment for different interfaces: staggered type for NN/KCl and straddling type for KCa/KCl interfaces. • Potential lineups are obtained, Δ V KCa/KCl =0 18 eV and Δ V NN/KCl =1.05 eV. [Display omitted] [ABSTRACT FROM AUTHOR]

This study assesses the effectiveness of empirical stability descriptors — the normalized geometric packing parameter, lattice size difference, electronegativities mismatch, and the convex hull analysis based on information on mutually dissolving components, and ab-initio calculated entropy forming ability (EFA) for high-throughput materials discovery in high-entropy ceramics. A sample containing 53,130 medium and high-entropy carbide combinations from the Materials Project database has been analyzed, comparing solid solutions selected based on empirical descriptors and EFA calculations. The suitability of various electronegativity scales is evaluated, while Automatic FLOW (AFLOW) partial occupation (AFLOW-POCC) and special quasirandom structures (SQS) calculations provide insights into enthalpies, bulk moduli, and lattice parameters. It is shown that local distortions play a role in determining the stability of high-entropy ceramics and estimated lattice parameters, Young's modulus, fracture toughness, and Vickers hardness by computational and experimental approaches. Our analysis demonstrates the efficacy of density functional theory (DFT) approaches for high-throughput screening and highlights the need for the further exploration of the cocktail effect on high-entropy ceramics' mechanical properties. [ABSTRACT FROM AUTHOR]

[Display omitted] Fluorite (CaF 2 , space group Fm 3 ¯ m) is an alkali-earth halide mineral with important and manyfold technological applications and for these means several experimental and theoretical investigations were performed to characterize the structural, electronic, optical, and elastic properties. However, a detailed knowledge of the thermodynamics and thermoelastic properties of fluorite in a wide temperature and pressure range is still missing. In this work, density functional theory simulations using the hybrid B3LYP functional and all-electron Gaussian-type orbitals basis sets were employed to model these properties between 0 – 1000 K and from 0 GPa to 7 GPa. The calculated PVT equation of state parameters were V 0 T = 42.278(7) Å3, K 0 T = 92.14(7) GPa, K' 0 T = 3.56(2) using a 3rd-order Birch-Murnaghan formulation, α 0 = 7.84(2) × 10–5 K−1 and α 1 = 2.17(3) × 10–5 K−1/2 from a modified Holland and Powell thermal equation of state, and a variation of the bulk modulus with temperature ∂ K 0 T /∂T = –0.0160(1) GPa K−1. The quality of the theoretical results was assessed by comparison with the few available data reported in the scientific literature, finding a general good agreement and extending the knowledge on this important technological material. [ABSTRACT FROM AUTHOR]

[Display omitted] • For the Cu 7 M, Cu 8 M, and Cu 9 M atomic clusters, the M metal atoms tend to be centered. • We found that the addition of transition metals enhanced the stability of clusters. • The addition of transition metals increased the adsorption energy of CO 2 clusters. • In the reaction of catalytic CO 2 reduction, CunNi was found to be the preferred catalyst. The efficient and selective electroreduction of CO 2 in chemical fuels can be environment-energy friendly; however, it highly relies on catalysts with controllable selectivity and reaction paths. At present, copper-based catalysts are a good option for CO 2 reduction, and the formation of C 1 + products is presented in this paper. First, we systematically studied the three-dimensional structures of the Cu 4-12 M clusters (a total of nine types). The M atoms were sequentially replaced by first-row transition metals (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn), which enhanced the stability of the clusters and their CO 2 adsorption energy. Second, studies on the catalytic reduction of CO 2 indicated that these clusters tend to produce methane through pathways mediated by CHO*. Finally, we summarized the lowest rate-determining steps of all clusters and identified the most suitable catalyst candidates. This work advances the theoretical study of nanoclusters for catalytic CO 2 reduction. [ABSTRACT FROM AUTHOR]

[Display omitted] A density functional theory (DFT)-based thermodynamic approach was applied to investigate the stability and analyze the surface electronic structures of potential termination structures for the Bismuth chromate (Bi 2 CrO 6) (0 0 1) surface. Five Bi 2 CrO 6 (0 0 1) surface terminations can be stabilized under certain thermodynamic equilibrium conditions, according to the constructed Bi-Cr-O surface phase diagrams, which are based on calculated surface Gibbs free energies. Analysis of the surface electronic structure shows that O-Bi surface termination has high potential for photocatalytic applications. Additionally, the work functions exhibit substantial differences across various Bi 2 CrO 6 surface terminations, implying that by selecting the thermodynamically more stable surface termination under suitable conditions, the performance of the direct Z-scheme heterostructure based on Bi 2 CrO 6 can be optimized. These findings offer a valuable approach for subsequent experimental research on Bi 2 CrO 6 -based photocatalysts and facilitate the investigation of the intrinsic characteristics of Bi 2 CrO 6 surfaces. [ABSTRACT FROM AUTHOR]

[Display omitted] • The machine-learned potential for aluminum was developed as based on Behler-Parrinello neural network scheme. • The potential demonstrates an excellent agreement with experimental data and DFT calculations concerning thermodynamic, elastic, liquid phase and generalized stacking fault energy properties. • High accuracy was achieved due to the optimal training set and configuration parameters used to generate the machine learning potential. Aluminum and its alloys are most often used as structural materials due to their specific properties, such as low weight, low energy consumption for remelting and the possibility of almost complete processing. This paper utilizes machine learning, specifically the Behler-Parrinello neural network scheme, to develop a powerful potential for studying the underlying mechanisms of deformation, fracture, and defect formation. By surpassing the limitations of first principles calculations, the application of machine-learned potentials (MLP) becomes highly advantageous for describing pure aluminum (Al) in its solid and liquid phases. Specifically, from the generated potential equilibrium, thermodynamic, elastic, and vibrational properties of face-centered cubic (fcc) Al are obtained in very good agreement especially with density functional theory (DFT) results as well as with previous calculations using existing semi-empirical potentials, such as EAM and MEAM, recent machine-learned potentials, and experimental data. Furthermore, our potential proves to accurately reproduce defect formation energies such as previously computed and measured stacking-fault energy curves. Finally, stacking fault profiles as well as key quantities of the liquid phase such as the melting point at ambient pressure, temperature-dependent densities, and radial distribution functions are also calculated in very good agreement with the results from previous theoretical and experimental investigations. Nevertheless, our investigation goes beyond previous studies in proving excellent agreement with experimental data especially of the specific heat and the melting point at very high pressures. The competitive analysis performed in this work thus clearly demonstrates the validity and accuracy of the generated machine-learned potential to describe a wide range of properties of Al at various temperatures and pressures and thereby lays ground for future applications. [ABSTRACT FROM AUTHOR]

In the density functional theory (DFT), it is well-known that the generalized gradient approximation (GGA) underestimates the energy gap. One of the commonly used GGA functionals is the Perdew–Burke–Ernzerhof (PBE) functional. This paper presents a machine learning approach to correct the energy gap estimated by PBE, using a minimal set of five features, to the accuracy level of the many-body perturbation theory G 0 W 0 band gap, which is known for its precision but high computational cost. These features are identified by seeking those which can be obtained directly from PBE-DFT calculations or from the standard atomic tables and directly connected to Coulombic interaction, and by minimizing feature correlations. The utilized features are the PBE band gap and the average atomic distance (obtained directly from PBE-DFT calculations) and the average oxidation states, electronegativity, and the minimum difference of electronegativity between constituents (obtained from the standard atomic tables). These features do not require any further atomistic calculations. The developed models are trained and validated using 265 inorganic semiconductors and insulators with energy gaps ranging from 0.75 to 14.55 eV. Several regression techniques have been applied, all of which have produced highly accurate and comparable results. This suggests that the five features employed in the analysis effectively capture the underlying physics. The most accurate model is based on Gaussian process regression (GPR), achieving a validation accuracy of 0.252 eV root-mean-square error (RMSE) and an R 2 value of 0.9932. The best bootstrapped model achieves an RMSE of 0.232 eV. The developed GPR model is then applied successfully to completely independent data sets. The developed model should allow calculating gaps with G 0 W 0 accuracy using the relatively much faster DFT-PBE. This is especially useful in materials discovery where computational efficiency is crucial. Furthermore, the model should allow empirical investigation of the influences of different compositional and structural characteristics on the gap. • Bandgap underestimation problem in DFT-PBE is corrected using machine learning with a minimal set of five features. • A Gaussian process regression achieved a validation RMSE of 0.252 eV and an R 2 of 0.9932. • Features are obtained directly from PBE-DFT calculations or from standard atomic tables. [ABSTRACT FROM AUTHOR]

BeO is a large band gap semiconductor with remarkably electronic, thermal and optical properties, being a potential material for nanodevices. In this work, using first principles calculations within the density functional theory and molecular dynamics simulations, we show that BeO is stable in the planar form (single-layer and single walled nanotubes). These nanostructures exhibit a large band gap (≈ 6 eV), being useful to host localized states. The stability of BeO layers upon the presence of native defects (vacancies and antisites) are investigated by calculating the formation energies as a function of the Fermi energy. The results have shown that in the neutral charge states, vacancies (V O and V B e) are the most likely defects to occur. For charge states, the defect stability is ruled by the Fermi energy position. The electronic band structure shows that natives defects give rise to spin localized electronic levels inside the band gap, which are stable in different charge states and can be thermally ionized. Furthermore, we investigate the optical properties (optical absorption spectra) and spin state (spin magnetic moments) for all stable defects. We observed that the spin localized states in the ground states lead the BeO layer materials to host quantum defects, which can be useful in quantum information. [Display omitted] • Layered BeO structures present a large band gap. • Native defects (vacancies and antisites) give rise to new electronic levels inside the band gap. • Native defects in layered BeO can be useful to generate localized states in the bandgap. • The stability and spin magnetic moments depend on the charge state. • Native defects in BeO layers can be considered as quantum defects. [ABSTRACT FROM AUTHOR]

In search of new electrode materials that improve rechargeable metal-ion batteries' performance, S-functionalized double-metal TiNbC MXene monolayer (TiNbCS 2) is designed, and its properties as an anode material for Li-, Na-, K-, Mg-, Ca-, and Al-ion batteries are investigated employing density functional theory. Due to technical issues during the preparation process, the surface of MXenes is mostly terminated by –O, –OH, and –F functional groups. It is possible to modify the surface by other terminal groups to improve MXenes' energy storage performance. According to our findings, the TiNbCS 2 monolayer, thanks to its metallic behavior, high chemical stability, low diffusion energy barriers, and low open-circuit voltages of these metal cations, is a promising anode material for rechargeable metal-ion batteries. Notably, the adsorption of multilayers of Na+ and Mg2+ cations on the surface of TiNbCS 2 provides excellent capacities of 494 mA h g−1 and 988 mA h g−1 for Na- and Mg-ion batteries, respectively. Although the trivalent Al ion may offer a higher energy density, our calculations show that Al3+ ions are not adsorbed onto the surface of the TiNbCS 2 monolayer effectively. [Display omitted] • S-functionalization of TiNbC MXene monolayer improves its energy storage performance. • TiNbCS 2 's properties make it a promising anode for rechargeable metal-ion batteries. • Adsorption of multilayers of cations on TiNbCS 2 provides excellent capacities for Na- and Mg-ion batteries. [ABSTRACT FROM AUTHOR]

In this study we present the results of our density functional theory calculations within the quasi-harmonic approximation, which predict formation and properties of a new compound of the garnet family, La 3 Sc 2 Al 3 O 12 (LSAG). LSAG was shown to be formed from 3LaAlO 3 + Sc 2 O 3 at ambient pressure and room temperature. The thermodynamic stability region of LSAG is limited by a temperature of 685 K, above which its decomposition into LaAlO 3 (LAP) and Sc 2 O 3 occurs. With increasing pressure, LSAG retains its stability up to 0.23 GPa, where the decomposition reaction LSAG ↔ 3LAP＋ Sc 2 O 3 becomes thermodynamically favorable. In this work, not only the thermodynamic stability of LSAG was assessed, but also its thermal conductivity, elastic constants and band gap were calculated. At 300 K the thermal conductivity of LSAG is 13.204 Wm−1K−1. LSAG has the smallest elastic constants compared with YSAG and YAG, which indicates weaker atomic bonding in LSAG than in YSAG and YAG. The width of band gap of LSAG calculated using an hybrid functional is equal to 5.24 eV. In addition, the P–T phase diagram of the known Y 3 Sc 2 Al 3 O 12 (YSAG) was calculated for the first time. Unlike LSAG, YSAG is stable at fairly high temperatures, reaching values of at least 1500 K. With increasing temperature to 1500 K, the pressure of the phase transition increases slightly to 3.55 GPa, and the monovariant curve of the reaction YSAG ↔ 3YAP+Sc 2 O 3 is represented by an almost straight line. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, we carried out systematic calculations on the Th-B binary compounds at high pressure from evolutionary algorithm and density functional theory. We discovered two possible pressure-stabilized phases Th 2 B and Th 2 B 5 in the Th-B binary system. Additionally, we found two thermodynamically metastable phases ThB 5 and Th 2 B 13 with unusual geometric structures, which exhibit considerable superconducting transition temperatures 22 K and 33 K at high pressures, respectively. [Display omitted] In this work, we carried out systematic calculations on the Th-B binary compounds at high pressure from evolutionary algorithm and density functional theory. We discovered two possible pressure-stabilized phases Th 2 B and Th 2 B 5 in the Th-B binary system. Additionally, we found two thermodynamically metastable phases ThB 5 and Th 2 B 13 with unusual geometric structures, which exhibit considerable superconducting transition temperatures 22 K and 33 K at high pressures, respectively. Furthermore, the discovery of Th 2 B 13 with a dumbbell-shaped truncated octahedral B atom cage structure, and ThB 5 with a B 20 -cage structure provides insights from the perspective of crystal geometry for the search of high temperature superconductors. [ABSTRACT FROM AUTHOR]

Experimental observations reveal that reactive elements (REs) function as sulfur-getters but do not completely pin sulfur (S) within the bulk, prompting a detailed exploration of interfacial segregation and its implications on the metal-oxide interface. Using first-principles, we investigate Hafnium (Hf) and Yttrium (Y)'s role in enhancing oxidation resistance in CoCrFeNi high-entropy alloy. Hf and Y segregation enhances interfacial adhesion and plasticity, whereas S segregation weakens and embrittles the interface. The pinning effect of Y is more pronounced compared to Hf at elevated temperatures. Co-segregation of Hf or Y with S mitigates deleterious effects, potentially improving HEA oxidation resistance. [Display omitted] • Hafnium and Yttrium enhance adhesion and plasticity of metal-oxide interface. • Sulfur segregation weakens and embrittles the interface. • Yttrium is more effective in pinning Sulfur at elevated temperatures. • Co-segregation of Yttrium or Hafnium with Sulfur mitigates the deleterious effects of Sulfur. • Thermal vibrations weaken the Reactive Element Effect. [ABSTRACT FROM AUTHOR]

The properties of nanoparticles depend on their sizes, and these size effects in face-centered-cubic (FCC) nanoparticles are attributed to the edge and vertex effects. However, the effects of edges and vertices on the properties of nanoparticles have not yet been explicitly investigated. In this study, we propose a method to evaluate the edge and vertex effects in FCC nanoparticles using density functional theory atomistic simulations. Pd and Au FCC nanoparticles are modeled as conventional truncated octahedra with { 111 } and { 100 } faces. The changes in the excess energy due to the edges and vertices are separately described and are calculated with respect to the size of the nanoparticles. Through explicit calculations, we confirmed that for Pd and Au nanoparticles with several hundred atoms, the vertex effects are negligible, whereas the edge effects are still significant. [Display omitted] • Pd and Au FCC nanoparticles modeled as conventional truncated octahedra. • Edge and vertex effects evaluated using density functional theory. • Explicit calculations to separately describe the edge and vertex effects. • For nanoparticles with several hundred atoms, edge effects are significant, however, vertex effects are negligible. [ABSTRACT FROM AUTHOR]

With massive influx of new funding and emergence of modern facilities and centers, the area of semiconductor manufacturing and processing has attained national and global momentum like never before. To meet the rising industry demands via accelerated materials design, fundamental atomistic-level insights are crucial. Today, there are a number of published works using some combination of first principles-based density functional theory (DFT) simulations and machine learning (ML) for accelerating the prediction of semiconductor properties over large chemical spaces. Materials discovery based on "DFT-ML" significantly shortens the time required to select promising chemistries for laboratory synthesis and characterization, and are thus frequently combined with rational experimentation for a variety of semiconductor classes and properties, for applications such as solar absorption, light emission, power electronics, photocatalysis, and quantum technology. In this review article, I discuss some of the key concepts behind accelerating the prediction of fundamental semiconductor properties, highlighting some available datasets and tools. In the context of published literature as well as my own past and ongoing research, I discuss some major studies involving the discovery of new materials for solar cells, water splitting, and wide band gap semiconductors, focusing on the application of DFT and/or ML for prediction and understanding of semiconductor alloys, bulk stability, electronic, optical, and dielectric properties, and defect behavior. This article aims to highlight established computational recipes, large databases, and ML-based prediction and optimization tools that may guide researchers in their own semiconductor design and discovery endeavors. [Display omitted] • This article discusses how DFT and ML accelerate the discovery of semiconductors. • Methods for predicting stability, electronic, optical, and defect properties are reviewed. • Best available materials datasets and ML models/tools are highlighted. • Several prominent literature examples are reviewed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multiscale calculations are performed to investigate electrified electrode–electrolyte interfaces for each of the 22 electrodes. • Three distinct types of charge state variations for metal ions dissolution are identified. • The non-integer equilibrium charge state of Copper (Cu) in an electrolyte is discovered. • A novel criterion for predicting the equilibrium charge states of ions in an electrolyte is proposed. The well-established phenomenon of solute atom dissolution from metal surfaces and their conversion into ions, with integer charges, as electrode potential increases has long been recognized. However, a critical question arises regarding the capability of Density Functional Theory (DFT) computations in predicting ions with integer charge states, given their reliance on probabilistic electron representations. This study introduces a more sophisticated perspective through comprehensive first-principles/continuum calculations, exploring the dissolution and deposition processes of 22 distinct metal elements across a broad range of applied electrode potentials. The outcomes illuminate three distinct dissolution models for various metals, thus offering fresh insights into this intricate phenomenon. Firstly, solute atoms exhibit an integer charge state following an integer-valence jump, aligning with classical understandings. Secondly, solute atoms attain an eventual integer valence, yet their charge state increases in a non-integer manner during dissolution. Lastly, we observe solute atoms exhibiting a non-integer charge state, challenging classical understandings. Furthermore, we propose a theoretical criterion for determining the selection of ion valence during electrode dissolution under applied potential. This discovery provides a novel perspective on our understanding of ion charge states. [ABSTRACT FROM AUTHOR]

[Display omitted] The structure, thermodynamic properties, and hydrogen storage capabilities of the complex hydride NaBH 4 have been analyzed by conducting first-principles calculations based on density functional theory (DFT). Additionally, the impact of Na substitution by Mg, Ca, and Mo has been explored. We focused on a stable α -NaBH 4 structure (space group symmetry F-43m (216)) to understand the effect of Mg, Ca and 3d transition metal on thermodynamic and dehydrogenation properties. It concluded that Mg, Ca and Mo at the Na site makes the B–H bond weaker than pure NaBH 4 , which improves the dehydrogenation properties. Among all the studied systems, the Mg-doped system demonstrates superior dehydrogenation characteristics in accordance with DOE guidelines. [ABSTRACT FROM AUTHOR]

[Display omitted] • Combination of classification model and regression model in machine learning. • First principles calculations. • Band gap of nonlinear optical crystals. Nonlinear optical crystals (NLO) are regarded as catalytic materials for photon coupling due to their characteristics of high conversion efficiency, tunability, and ease of manipulation. We aim to find superior performing NLO crystals by precisely estimating their bandgaps. Our approach involves utilizing compositional, structural, and orbital data as input features, leveraging models based on the Random Forest regression (RFR), Extreme Gradient Boosting (XGB), and Gradient boosting regression (GBR) regression algorithms. Notably, the RFR regression model in our research exhibited exceptional predictive performance, attaining an R2 value of 0.823, with an RMSE of 0.639 eV and an MAE of 0.470 eV per atom. Our model works well on a small dataset. Moreover, we incorporated Shapley Additive exPlanations (SHAP) analysis to elucidate the rationale behind predictions by assessing the contribution of each feature to the bandgap. To verify the reliability of our model, we selected three traditional crystals and conducted first-principles electronic structure calculations. We compared the predicted values from our model with those computed using the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional, ensuring an error margin of approximately 0.5 eV, thus confirming the precision of our model. These models facilitate swift and cost-effective predictions of bandgaps in NLO crystals. [ABSTRACT FROM AUTHOR]

[Display omitted] • Volume distortion upon doping of the alloying elements predominantly influences their grain boundary segregation behavior. • The weak bonding between Zn and Fe is responsible for the grain boundary embrittlement. • The mechanical contributions in the grain boundary strengthening energy correlate linearly with variations in the volume of the doping site. • The chemical contributions in the grain boundary strengthening energy correlate linearly with changes in bond energy for bonds associated with the doping site. • B and Mo are the most promising elements to mitigate the Zn-induced liquid metal embrittlement. Liquid metal embrittlement (LME) induced by Zn melt in galvanized steels during spot-welding poses a significant challenge to the advancement of the automotive industry. A critical strategy to address this challenge is identifying promising alloying elements capable of mitigating LME. High-throughput first-principles calculations were employed to investigate the segregation behavior of 22 common alloying elements at the Σ5(3 1 0) grain boundary of iron and their impact on the grain boundary energy. The results indicate that volume distortion upon doping of the alloying elements predominantly influences their segregation behavior, while the weak bonding between Zn and Fe is responsible for the grain boundary embrittlement. Exploration of solute interaction between Zn and the other alloying element in the Fe grain boundary model reveals that the attraction between metallic doping elements and Zn correlates with both the elastic effects and the magnetic properties of the dopant, while the repulsion between non-metallic elements and Zn is primarily governed by the elastic effects. Separating the grain boundary strengthening energy into mechanical and chemical contributions shows that they correlate linearly with variations in volume of the doping site and changes in bond energy for bonds associated with the doping site at the grain boundary, respectively. Accordingly, the strengthening effect of the doping elements can be estimated by evaluating the induced changes in local volume and bond energies on grain boundaries. Furthermore, potential alloying elements to mitigate the Zn-induced LME are screened and discussed, with B and Mo being the most promising candidates. [ABSTRACT FROM AUTHOR]

Porous two-dimensional (2D) materials with semiconducting property are promising candidates for a variety of multifunctional energy harvesting applications. Motivated by the successful synthesis of porous organic biphenylene and graphenylene materials, herein, we demonstrate the ground-state properties of a new family of b-BX and g-BX monolayers inorganic biphenylene and graphenylene monolayers using first-principles calculations based on density functional theory. Stability tests show that the b-BX and g-BX monolayers are energetically, mechanically, dynamically, and thermally stable. Moreover, g-BX (X = As, Sb) monolayers are auxetic 2D materials. According to the HSE06 electronic band structure results, these monolayers of b-BX and g-BX exhibit moderate and wide indirect bandgap semiconducting properties. These novel ground state properties of b-BX and g-BX monolayers demonstrate their aforementioned potential applications in addition to optoelectronic, thermoelectric, and flexible electronics. Besides all these newly proposed b-BX and g-BX monolayers expand the family of inorganic biphenylene and graphenylene non-magnetic materials. [Display omitted] • The BX (X = P, As, Sb) bi-/graphe-nylene monolayers have been investigated using DFT calculations. • BX monolayers have been found to be stable. • BX (X = As, Sb) graphenylene monolayers are auxetic 2D materials. • BX monolayers exhibit moderate and wide indirect bandgap semiconducting properties. [ABSTRACT FROM AUTHOR]

[Display omitted] Carbide nano-precipitates are commonly used to improve mechanical properties of steel. It has been experimentally observed that TiC, NbC, and VC carbide precipitates initially form as 'plate-like' particles oriented in the {1 0 0} planes of the ferrite lattice. These platelets share similarities with Guinier-Preston zones in Al-Cu alloys. The clustering of group IV and V transition metal atoms (M = Ti, Zr, Hf, V, Nb, Ta) in ferrite is studied using density functional theory. It is deduced that the transition metal carbides all form in a similar way. Furthermore, the transition from an initial M–C cluster to a NaCl-structured platelet to a NaCl-structured precipitate is examined through atomistic simulations using Modified Embedded Atom Method potentials. A route is established along which transition metal carbides form and transform into precipitates that possess the Baker-Nutting orientation relation with the ferrite matrix. [ABSTRACT FROM AUTHOR]

New materials with magnetic order driven topological phases are hugely sought after for their immense application potential. In this work, we propose a new compound EuMn 2 Bi 2 from our first principles density functional theory calculations to host novel topological phases such as Dirac/Weyl semimetal and topological insulator in its different magnetic states which are energetically close to one another. The new compound EuMn 2 Bi 2 is found to be dynamically stable from our phonon calculations supporting its experimental preparation in future. By comparing the total energies of various possible magnetic structures of EuMn 2 Bi 2 , we identified the ground state. The magnetic ground state is found to be a normal insulator with tiny band gap which is an order of magnitude less than the same in another well studied sister compound EuMn 2 As 2. However, there exist other magnetic states energetically very close to the ground state in EuMn 2 Bi 2 which display remarkable non-trivial band topology such as Dirac/Weyl points close to the Fermi level and topological insulator state driven by magnetic order which is not observed in EuMn 2 As 2. The energetic proximity of these magnetic order driven topological phases makes them tunable via external handle such as magnetic field indicating that the proposed new material EuMn 2 Bi 2 would be a very versatile magnetic topological material if prepared experimentally in future. • A new magnetic topological compound EuMn 2 Bi 2 is proposed from first principles. • EuMn 2 Bi 2 can be tuned from Dirac semimetal to topological insulator in G0-AFM phase. • It can go from Weyl semimetal to normal insulator in C0-AFM phase. • EuMn 2 Bi 2 is dynamically stable hence can be prepared in future experiments. • Magnetic field can be used to access different topological phases. [ABSTRACT FROM AUTHOR]

[Display omitted] • A deep-learning molecular dynamics potential of rare-earth Sc was developed. • The DP model correctly captures the HCP structure as the stable phase of Sc. • The HCP-BCC transformation temperature of Sc predicated by the DP model is 1622 K. • The DP model accurately reproduces the shape of GSFE curves and the γ usf ordering. The deep potential (DP) is a promising deep-learning-based approach to developing the high-accurate potential function of various materials from the data of ab-initio calculations based on density functional theory (DFT). To better understand the structural and physical properties of the rare-earth metal scandium (Sc), performing classical molecular dynamics (MD) simulations should be highly beneficial but has been straitened for lacking of available Sc potential. Therefore, the necessary interatomic potential function of Sc for MD simulations was developed first in this work by using the DP method. By systematically comparing the DP-predicted lattice constants, stable phase, vacancy and self-interstitial formation energies, surface energies, elastic constants and generalised stacking fault energy curves with the corresponding DFT results, we validated that the developed DP model of Sc enables these property-predictions with a reasonable DFT accuracy. Moreover, our DP-based MD simulations shown that the rare-earth Sc can transform from the α-HCP to the β-BCC structure at 1622 K and melt at 1710 K, quite close to the experimental values for the α-β phase transition temperature (1609 K) and the melting-point (1814 K) of Sc. Rising temperature can improve the diffusivity of Sc atoms and the self-diffusion coefficient at the melting-point is 5.7 × 10−12 m2/s, which is on the same order of magnitude as other HCP metals. The results could be used for understanding the fundamental properties of rare-earth metal Sc and as a basis for further developing the Sc-containing binary or multinary DP models. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electronic properties and frontiers molecular orbitals of ProNit-GO revealedreactive regions. • Obtained equilibrium adsorption configuration confirmed the horizontal adsorption ProNit-GO. • ProNit-GO adsorbed on the Fe(1 1 0) plane in horizontal fashion leads to greater surface coverage and protection ability. • Adsorption energy confirmed the spontaneity of adsorption of ProNit-GO on the Fe(1 1 0) plane. The adsorption mechanism corroborating the corrosion inhibition effects of graphene oxide (GO) modified with L-proline nitrate (ProNit) ionic liquid, ProNit-GO, on iron surface was investigated using ab initio density functional theory (DFT) and Monte Carlo (MC) simulation techniques. The electronic density distribution along with various electronic properties, including frontier molecular orbitals primarily highest occupied molecular orbital, lowest unoccupied molecular orbitals, energy gap, reactivity, and hydrogen bonding interactions between L-proline nitrate and graphene oxide stabilizing ProNit-GO adduct interacting through different sites of interactions, were examined through DFT calculation which revealed different reactive sites within ProNit-GO and its reactivity. Additionally, the MC simulation investigation of ProNit-GO on iron surface has unveiled its remarkable propensity for spontaneous interaction and favored adsorption energetically ascertained from the highly negative magnitude of adsorption energy. Furthermore, MC simulation results revealed a horizontally aligned disposition of ProNit-GO onto targeted Fe(1 1 0) surface suggesting the adsorption of ProNit-GO onto iron surface and protective film formation. The adsorbed ProNit-GO acted as barrier layer that inhibit the penetration of corrosive electrolytes or species towards the susceptible iron surface exposed into the corrosive electrolyte. Hence, the corrosion inhibitory effects of ProNit-GO on iron surface can be deliberated upon. [ABSTRACT FROM AUTHOR]

Advancements in modern semiconductor devices increasingly depend on the utilization of amorphous materials and the reduction of material thickness, pushing the boundaries of their physical capabilities. The mechanical properties of these thin layers are critical in determining both the operational efficacy and mechanical integrity of these devices. Unlike bulk crystalline materials, whose calculation techniques are well-established, amorphous materials present a challenge due to the significant variation in atomic topology and their non-affine transformations under external strain. This study introduces a novel method for computing the elastic tensor of amorphous materials, applicable to both bulk and ultra-thin films in the linear elastic regime using Density Functional Theory. We exemplify this method with a-SiO 2 , a commonly used dielectric. Our approach accounts for the structural disorder inherent in amorphous systems, which, while contributing to remarkable material properties, complicates traditional elastic tensor computation. We propose a solution involving the inability of atomic positions to relax under internal relaxation, near the boundaries of the computational unit cell, ensuring the affine transformations necessary for linear elasticity. This method's efficacy is demonstrated through its alignment with classical Young's modulus measurements, and has potential for broad application in fields such as Technology Computer Aided Design and stress analysis via Raman spectra. The revised technique for assessing the mechanical properties of amorphous materials opens new avenues for exploring their impact on device reliability and functionality. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] Black phosphorene (BlackP) with low diffusion barriers has been extensively researched as one of the new Li-ion batteries (LIBs) anode materials. Nevertheless, the poor mechanical properties and elastic stiffness of BlackP obviously limit its practical application. Thus, owing to the excellent mechanical properties and good elastic stiffness exhibited by Graphdiyne (GDY), the BlackP/GDY Van der Waals (vdW) heterostructure was investigated in our study to overcome those disadvantages on the basis of the density functional theory (DFT). Our results suggest that the BlackP/GDY vdW heterostructure has favorable mechanical properties and high thermodynamic stability with a small lattice mismatch, which is owing to the synergistic effect existed in BlackP and GDY. Besides, the adsorption energy of Li adsorption on the BlackP/GDY vdW heterostructure evidently enhanced along with the changing of the heterostructure from semiconductor to metallic. Moreover, the maximum theoretical storage capacity (384.703 mA h/g) of the BlackP/GDY vdW heterostructure is larger than that of Graphite (372 mA h/g). Above all, the minimum diffusion barrier (0.083 eV) is extremely low, which is vital for achieving ultrafast charge and discharge rates. These favorable advantages suggest that the BlackP/GDY vdW heterostructure is a viable ultrafast LIBs anode material. [ABSTRACT FROM AUTHOR]

We employed a Monte-Carlo optimization scheme to successfully create a novel ReaxFF parameter set tailored for the exploration of the structures and energetics of Mo-S-C materials. This force field underwent rigorous testing against Density Functional Theory (DFT) data and exhibited its efficacy in modeling a broad spectrum of structures, ranging from composite heterolayer 2D structures to fully amorphous coatings. Subsequently, we applied this force field to get insights into the structural formation of amorphous MoS 2 -C films. Our simulations yielded promising results, revealing, in agreement with the experimental findings, preferential formation of Mo-S and C-C bonds along with rapid phase segregation. [Display omitted] • A new ReaxFF parameter set to describe bonding and energetics of Mo-S-C materials. • ReaxFF and DFT correspond within 0.1 eV/atom for a wide range of structures. • Simulated realistic kinetics of structure formation in amorphous Mo-S-C. [ABSTRACT FROM AUTHOR]

The s → p band structure refers to a band structure where the s -orbital contributes to the VBM, and the p -orbital contributes to the CBM, whereas the p → s band structure signifies a band structure where the p -orbital contributes to the VBM and the s -orbital contributes to the CBM. The PBE-calculated band gap is underestimated for semiconductor materials with a p→s band structure, whereas it is slightly overestimated for those with an s→p band structure. Despite reductions in band gap errors with smaller band gaps, these errors persist even as the band gap approaches zero due to wavefunction discontinuities between the VBM and CBM, contrasting with metal systems. [Display omitted] This study addresses the prevalent band gap error problem in density functional theory (DFT) with local density or generalized gradient approximation (LDA/GGA), widely considered as the "standard model" for investigating the band structure of semiconductors. Despite previous DFT efforts focusing on improving the exchange correlation energy to mitigate the underestimation of the band gap, the correlation between the band gap error and the intrinsic electronic structure of semiconductors has been overlooked. From two principal observations: (i) traditional semiconductors typically have a p-s type band structure, and (ii) a smaller band gap is linked to less underestimation, we derive two crucial questions: (i) How is band gap error manifested in s - p type semiconductors? (ii) Does the error vanish as the band gap approaches zero, akin to metals? Through the examination of CdTe and GeTe, representing p – s and s – p type semiconductors with strain-engineered band gaps, our calculations indicate that for CdTe, the band gap is underestimated, whereas for GeTe, it is overestimated. Significantly, these errors persist even as the band gap of semiconductors tends to zero, unlike in metals. This persistent discrepancy stems from the discontinuity in wavefunctions between the semiconductors' VBM and CBM. [ABSTRACT FROM AUTHOR]

[Display omitted] • Short-range orders in different phases of Al x CoCrFeNi were identified/quantified. • Most and least favored element pairs were identified in the high-entropy alloys. • Effects of short-range orders (SROs) on thermodynamic behaviors were found. • Correlation between dominant pairs and thermal conductivities were quantified. • Reduced phonon broadening was observed in the high-entropy alloys with SROs. Short-range order (SRO) in high-entropy alloys (HEAs) has been observed both computationally and experimentally in recent studies. Despite their recognized influence on the physical properties of the HEAs reported, a comprehensive work on the relationship between SRO and the tuning of the thermodynamic properties of HEAs has been lacking. In this research, to identify the SRO-property relationship, the Warren-Cowley (WC) parameters, which quantify the degree of SRO, and thermodynamic properties in Al x CoCrFeNi HEAs were investigated, utilizing the molecular dynamics (MD) simulations, hybrid molecular dynamics/Monte Carlo (MD/MC) simulations, and density functional theory (DFT) calculations. We examined SROs in different phases of Al x CoCrFeNi HEAs by varying aluminum (Al) contents (x Al) ranging from 0 to 2.0. Results reveal a prevalent negative SRO of Al-Fe and positive SRO of Al-Al pairs across all HEA cases. Under the influence of SRO parameters, lattice thermal conductivity and bulk modulus exhibit higher values, whereas coefficient of thermal expansion exhibits lower values. This research advances our understanding of the SRO-properties relationship in HEAs, contributing to the design of HEAs with tailored properties through structural tuning. [ABSTRACT FROM AUTHOR]

[Display omitted] • The quadratic energy—occupation relation is verified for DFT-1/2, within LDA as well as GGA. • The choice of self-energy potential is crucial for calculating ionic insulations using DFT-1/2. • Default choice in DFT-1/2 tends to yield smaller band gaps for fluorites but larger band gaps for nitrides. • Solution to the DFT-1/2 band gap problem in ionic insulators is prescribed. DFT-1/2 is an efficient band gap correction method for density functional theory under local density approximation or generalized gradient approximation. Nevertheless, it still predicts lower band gaps than experimental in highly ionic insulators, such as LiF and CsCl. In this study, we emphasize that the problem is more severe for halides. For example, the DFT-1/2 band gap for Li 2 O is much more satisfactory than that for LiF. Notwithstanding the traditional belief that high ionicity is the key, we ascribe the main reason to the fact that the self-energy potentials (SEPs) used for anions were derived based on neutral atoms. Extensive tests have shown that an SEP derived from an atom/ion with fewer electrons is stronger than that derived with more electrons. The degree of enhancement in the O SEP, based on O rather than O2–, could generally compensate for the loss of SEP in the trimming process. In the case of halides, such compensation is insufficient, resulting in small band gaps. For ionic nitrides involving N3–, the SEP is undesirably large if it is derived from a neutral N atom. Equivalent scaling factors are prescribed for the SEPs of F and N, with the former being greater and the latter being smaller than unity. With proper SEP scaling factors according to the charge carried by the anion, the DFT-1/2 band gaps are greatly improved for highly ionic insulators. [ABSTRACT FROM AUTHOR]

[Display omitted] Metal-halide perovskites, particularly inorganic cesium-lead halide perovskites, have emerged as exceptional candidates for several technological applications in the 21st century, such as photovoltaic devices, optoelectronic and photocatalysis. This study systematically investigates the CsPbI 3 surfaces through density functional theory (DFT) simulations and morphological analyses. The (0 0 1), (1 1 0), and (1 1 1) surfaces were investigated in terms of their possible terminations (here named α , β , γ , δ and ε), where the relations between their outermost coordination polyhedra, bond lengths, charge distribution, electronic and morphological properties were revealed. The results demonstrate that the (0 0 1) and (1 1 0) surfaces stand out as the most stables, with E s u r f 001 - α = E s u r f 110 - γ = 0.08 J / m 2. Concerning the electronic properties, it is observed that the (1 1 0) and (1 1 1) present α terminations with acceptor states, while the β with donor states, making it possible to tune the system semiconducting behavior (n or p-type) via surface termination control. The Wulff construction was employed to show that (0 0 1), (1 1 0) and (1 1 1) surface stabilizations can produce cubic, dodecahedral and octahedral nanocrystal morphologies, respectively. By probing the depths of CsPbI 3 surfaces, this research advances new concepts about the design and functionalization of perovskite halide, offering a crucial direction for experimental synthesis strategies. [ABSTRACT FROM AUTHOR]

A computational approach combining dispersion-corrected density functional theory (DFT) and classical molecular dynamics is employed to characterize the geometrical and thermomechanical properties of a recently proposed 2D transition metal dihalide NiCl 2. The characterization is performed using a classical interatomic force field whose parameters are determined and verified through the comparison with the results of DFT calculations. The developed force field is used to study the mechanical response, thermal stability, melting and solidification of a NiCl 2 monolayer on the atomistic level of detail. The 2D NiCl 2 sheet is found to be thermally stable at temperatures below its melting point of ∼ 695 K. At higher temperatures, several subsequent structural transformations of NiCl 2 are observed, namely a transition into a porous 2D sheet and a 1D nanowire. The MD simulations of NiCl 2 cooling show that the molten NiCl 2 system solidifies into an amorphous porous 2D structure at T ∼ 450 K. The resulting structure has lower cohesive energy with respect to the initial 2D sheet. The computational methodology presented through the case study of NiCl 2 can also be utilized to study the properties of other novel 2D materials, including recently synthesized NiO 2 , NiS 2 , and NiSe 2. [Display omitted] • A 2D NiCl 2 material is characterized computationally using DFT and classical MD. • A classical force field for NiCl 2 is developed. • Parameters of the force field for NiCl 2 are benchmarked against the DFT results. • Thermomechanical properties of the 2D NiCl 2 material are investigated. • Structural transformations of a 2D NiCl 2 sheet above its melting point are explored. [ABSTRACT FROM AUTHOR]

• Search for new metal borides by combining crystal structure prediction and cluster expansion. • High-throughput analysis on identified low-energy structures. • Nine predicted stable (M' 1/3 M" 2/3) 3 AlB 4 phases. • Five which favour disordered M-sites and four ordered M-sites. A desired prerequisite when performing a quantum mechanical calculation is to have an initial idea of the atomic positions within an approximate crystal structure. The atomic positions combined should result in a system located in, or close to, an energy minimum. Designing low-energy structures for large multi-component systems is, however, often a challenging task as the degrees of freedom are close to infinite. The low-energy basins of (M′ x M″ 1-x) 3 AlB 4 material systems are herein explored by combining cluster expansion and crystal structure prediction methodologies with density functional theory calculations. Low-energy structures are specifically found at the (M′ 1/3 M″ 2/3) 3 AlB 4 composition, and this for multiple crystal symmetries. A subsequent high-throughput phase stability search was performed considering the identified low-energy structures at the (M′ 1/3 M″ 2/3) 3 AlB 4 composition where M′ and M″ were alloyed with Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, and Co for both ordered and disordered structures. Nine quaternary phases were predicted stable with five of these favoring structures with M-sites in the form of a simulated solid solution. [ABSTRACT FROM AUTHOR]

[Display omitted] • Na 4 Mn 4 Ti 5 O 18 have been studied for the evaluation of redox action for sodium ion battery application. • Mn atoms presents in octahedral site act as main redox center with redox couple Mn+3/Mn2+δ. • Mn atoms in square pyramidal sites act as partial redox center with redox couple Mn+3/Mn3−γ. • The redox voltage for intercalation and de-intercalation in Na 4 Mn 4 Ti 5 O 18 is found to be 2.63 V and 3.82 V respectively. • Experimental band gap of Na 4 Mn 4 Ti 5 O 18 (0.9 eV) is found to be closely matching with the simulated band gap (1.064 eV). • With intercalation and de-intercalation, the bandgap decreases to 0.645 eV in Na 6 Mn 4 Ti 5 O 18 and 0.93 eV in Na 2 Mn 4 Ti 5 O 18. Density functional theory study has been performed on Na 4 Mn 4 Ti 5 O 18 to evaluate its application feasibility as an electrode in Na ion battery. Two types of void in the structure of Na 4 Mn 4 Ti 5 O 18 , viz., Z shaped tunnel and polyhedral pentagonal void, has been observed that act as guest sites for reversible migration of Na+ ions. It is also noted that electrochemically active sites are placed in Z shaped tunnel that act as host for Na+ during anodic response while it acts as the Na+ donor during cathodic response. The Mn atom, located in the Z-shape tunnel, acts as redox active site for both cathodic and anodic response via formation of redox couple Mn+3/Mn+4 and Mn+3/Mn+2 respectively. On the other hand, Mn atom present at square pyramidal site remains inert during charge–discharge process. The redox action in Na 4 Mn 4 Ti 5 O 18 , occurring due to intercalation and de-intercalation of 2Na+ ions per formula unit, has been noted to exhibit voltage ∼2.63 V and 3.82 V respectively. The theoretical capacity ∼128 mAhg−1 has been estimated corresponding to migration of 2Na+ in Na 4 Mn 4 Ti 5 O 18 structure. The present simulation study indicates the possibility of electrode action in Na 4 Mn 4 Ti 5 O 18 for sodium ion battery application. [ABSTRACT FROM AUTHOR]

Novel two-dimensional B x S y materials with biphenylene network structure. [Display omitted] • A novel series of 2D-B x S materials with biphenylene (BP) network structures. • B 2 S and B 3 S exhibit remarkable thermal and mechanical stability. • The mechanical and optical properties of them exhibit anisotropy. • They display a broad spectrum of light absorption capabilities. • Potential photocatalysts for HER with their catalytic activity being pH-dependent. Two-dimensional (2D) boron-sulfur (B x S y) materials have garnered significant attention due to their potential applications in optoelectronic devices, catalysis, and energy conversion. In this study, we have innovatively designed a series of 2D-B x S materials (x = 2, 3, 5) with biphenylene (BP) network structures, denoted as BP-like B x S. Density functional theory calculations reveal that, with the exception of B 5 S, the metallic B 2 S and B 3 S exhibit exceptional thermal and mechanical stability, showcasing anisotropic mechanical and optical properties. Furthermore, B 2 S and B 3 S demonstrate a broad spectrum of light absorption capabilities, spanning from infrared to ultraviolet and visible light. Remarkably, these materials exhibit promising photocatalytic activity for the hydrogen evolution reaction (HER), with limiting potentials (U L) of 0.55 eV for B 2 S and 0.94 eV for B 3 S, respectively. The catalytic behavior is pH-dependent, with B 2 S favoring acidic conditions and B 3 S favoring alkaline conditions, where U L for B 3 S can reach 0.28 eV at pH = 12.58. This work reports BP-like B x S materials for the first time, thereby enriching the B x S y material family and extending their properties and potential applications in the fields of optoelectronics and catalysis. [ABSTRACT FROM AUTHOR]

The Set of Small Ordered Structures (SSOS) approach is an ab initio technique for modelling random solid solutions in which many small structures are averaged so that their correlation functions match those of a desired composition. SSOS has been shown to be effective in reducing the cost of density functional theory calculations relative to other well-known techniques such as cluster expansions and special quasirandom structures for modelling solid solutions. In this work, we demonstrate that SSOS's can be constructed using cells with only a subset of elements while still accurately modelling multi-component systems. Specifically, we show that small binary cells can effectively model two quinary high entropy alloys – NbTaTiHfZr and MoNbTaVW – accurately capturing properties such as formation energy, lattice parameters, elastic constants, and root-mean-square atomic displacements. Overall, this insight is useful for those looking to construct databases of such small structures for predicting the properties of multi-component solid solutions, as it greatly decreases the number of structures that needs to be considered. [Display omitted] • Properties of two high entropy alloys are modelled using the SSOS approach. • We show small binary cells are sufficient to predict several properties of interest. • NbTaTiHfZr and MoNbTaVW systems are searched for optimal Pugh's ratio compositions. [ABSTRACT FROM AUTHOR]

[Display omitted] The dissociative adsorption of O 2 demonstrates a significant correlation with the catalytic efficiency of oxygen reduction catalysts. We have performed density-functional theory calculations to investigate the dissociative adsorption of O 2 on the Pd-skin Pd 3 Cu(1 1 1) surface. The calculated results show that the adsorption configuration denoted as "t-f(h)-b" is energetically favourable on the Pd-skin Pd 3 Cu(1 1 1) surface. In the context of O 2 dissociation, two thermodynamically favourable dissociation pathways have been identified. The first pathway proceeds from the initial state denoted as "t-f-b" to yield two oxygen atoms occupying hcp sites. The second pathway, starting from "t-h-b," leads to the formation of two oxygen atoms positioned at fcc sites. Furthermore, our analysis demonstrates a decrease in the stability of O 2 adsorption and a slight increase in the energy barrier for the dissociation of adsorbed O 2 compared to the corresponding process on the Pd(1 1 1) surface. This theoretical investigation offers valuable insights that can inform and guide the practical application of Pd-Cu alloy materials as highly effective catalysts for oxygen reduction reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gold-based perovskites CsAu X 3 were found to be stable thermodynamically. • The perovskites exhibit mechanical stability and were observed to be ductile. • They were found to possess appropriate indirect bandgap for photovoltaic applications. • Light-effective masses and small exciton binding energies were observed from the materials. Perovskite materials have generated research attention in recent times owing to their potential to be deployed as photovoltaic materials. In this study, an examination of the structural, mechanical, electronic, and optical properties of CsAu X 3 (X = C l , B r , a n d I) perovskite materials was conducted using the Density Functional Theory to determine their suitability in photovoltaic applications. The findings revealed they were both thermodynamically and mechanically stable. The perovskites were also found to be elastically anisotropic. Suitable semiconducting indirect bandgaps of 1.38 eV, 1.17 eV, and 1.07 eV were predicted for CsAu Cl 3 , CsAu Br 3 , and CsAu I 3 respectively using hybrid HSE06 functional. The absorption coefficient decreased from ultraviolet through the visible to the infrared region for all the perovskite materials. The static dielectric constants increased as Cl was replaced with Br and I suggesting improved photovoltaic properties. The effective masses of holes and electrons together with the exciton binding energy were computed to demonstrate the ease of generating electron-hole pair for the studied perovskites. These perovskite materials, based on the findings of this study may be considered as having potential for applications in the photovoltaic industry. [ABSTRACT FROM AUTHOR]