Janus two-dimensional (2D) materials are a unique class of materials with asymmetrically functionalized surfaces. This asymmetry can enable multifunctional applications in fields such as optoelectronics, energy storage, and catalysis. The present study explores the properties of hydrogen-enriched VSH Janus monolayer, derived from VS2 transition metal dichalcogenide, as potential anode material for lithium-, sodium-, and calcium-ion batteries. Using first-principles calculations, we demonstrate that the semiconductor VSH Janus undergoes a transition to a metallic state upon interaction with a single metal ion, highlighting its promising electrochemical properties. Phonon dispersion and ab-initio molecular dynamics simulations confirm the dynamic and thermal stability of VSH. Additionally, our results show high net charge transfer rates and pronounced electron localization, indicative of strong ionic bonding in the Ca/Na/Li-VSH systems. Projected crystal orbital Hamiltonian population analysis reveals ionic interaction between metal ions and system elements, along with low diffusion energy barriers (<0.26 eV) and open circuit voltages (<0.43 V). Furthermore, VSH demonstrates high specific storage capacities of 4466.83 mAh g(-1), 638.11 mAh g(-1), and 850.82 mAh g(-1) for Li+, Na+, and Ca2+ ions, respectively. These findings indicate that the VSH Janus shows great potential as an anode material for Li+-, Na+-, and Ca2+-ion battery applications.

The Rashba effect, originating from spin-orbit interaction and crystal asymmetry, enables electric-field control of electron spins, making materials with strong Rashba splitting near the Fermi level attractive for spintronics. Using first-principles calculations, we identify asymmetric Bi2O2Se monolayer as a semiconductor exhibiting large Rashba splitting. Its structure induces a work function difference (Δϕ) of 3.25 eV, dipole moment of 0.32 D, and a small band gap of 0.30 eV. The conduction band shows Rashba energy ER = 33.6 meV and coupling constant αR = 10.56 eV Å with circular spin texture around the Γ point. The monolayer remains mechanically stable under ± 10% strain, while strain and electric fields (≤0.3 V/Å) reversibly tune polarization and Rashba splitting. A finite out-of-plane spin component (Sz) emerges from anisotropic SOC, demonstrating experimentally feasible and controllable spin-texture modulation. Both ER and αR increase under tensile strain, highlighting Bi2O2Se’s potential for high-efficiency spin-field-effect transistors and advanced semiconductor spintronics. (Figure presented.) 

Solar cells are expected to become one of the dominant electricity generation technologies in the coming decades. Developing high-performance absorbers made from thin materials is a promising pathway to improve efficiency and reduce cost, accelerating the widespread adoption of these photovoltaic cells. In the present work, we have systematically investigated the 2D MoSi2N4/Arsenene van der Waals (vdW) heterostructure, which exhibits a type-II band alignment with an indirect band gap semiconductor (1.58 eV), that can effectively separate the photogenerated electron–hole (e−–h+) pairs. Compared to the isolated MoSi2N4 and Arsenene monolayers, the optical absorption strength can be significantly enhanced in MoSi2N4/Arsenene vdW heterostructure (in the order of ∼105 cm−1 in the visible region). The calculated optical absorption gaps are 2.12 eV (Arsenene) and 1.76 eV (MoSi2N4), with excitonic binding energies of 0.05 eV for arsenene and 0.48 eV for MoSi2N4, indicating that both materials can effectively form excitons and separate charges. Moreover, we found a high spectroscopic limited maximum efficiency of 27.27% for the MoSi2N4/Arsenene vdW heterostructure, which is relatively higher compared to previously reported 2D heterostructures. Ab-initio molecular dynamics (AIMD) simulations at 300 K, 600 K, and 900 K were conducted to evaluate the thermal stability of the MoSi2N4/Arsenene heterostructure. Simulations in the presence of water and NO2 at 300 K were also performed to assess its resilience to humidity and pollutants. The results suggest strong stability under harsh environmental conditions. Our findings demonstrate that the 2D MoSi2N4/Arsenene vdW heterostructure is an excellent candidate for both photovoltaic device applications and optoelectronic nanodevices.

Cemented carbides are widely used materials in industrial applications due to their remarkable combination of hardness and toughness. However, they are exposed to high temperatures during service leading to a reduction of their hardness. A common practice to damp this softening is to incorporate transition metal carbides in cemented carbide compositions, which keeps the hardness relatively higher when temperature increases. Understanding the underlying mechanisms of this softening is crucial for the development of cemented carbides with optimal properties. In this work, atomic-scale mechanisms taking place during plastic deformation are analyzed and linked to the effect that they have on the intrinsic macro-scale softening of the most common TMC used in cemented carbides grades (TiC, ZrC, HfC, VC, NbC and TaC). The proposed model uses the generalized stacking fault energy obtained from density functional theory calculations as an input to Peierls-Nabarro analytical models to obtain the critically resolved shear stress needed for deformation to occur in different slip systems. Subsequently, this information is used to predict the hardness variation across the temperature service range experienced by cemented carbides in wear applications. In addition to the prediction of hot-hardness for TMC, the obtained results also offer valuable insights into the intrinsic mechanisms governing TMCs deformation. The results facilitate the identification of dominant dislocation types influencing plasticity within distinct temperature regimes, define energetically favorable slip systems, and predict the brittle-ductile transition temperature in these materials. For instance, for group IV carbides at low temperatures, the slip system with a lower GSFE is {110}<11̅0> and around 30% of their melting temperature, the GSFE of partial slip in {111}<12̅1> becomes lower, changing the dominant slip mechanism and characterizing the Brittle-Ductile transition.

Energy storage technologies that can meet the unprecedented demands of a sustainable energy system based on intermittent energy sources require new battery materials. In recent years, new superionic conducting glasses have been discovered that have captured the attention of the community due to their potential use as solid electrolytes for all-solid-state Li-ion batteries. New research is needed to understand the correlations between the non-crystalline structure of glasses and their advanced properties. Here we investigate the structural properties, the electronic structure and the electrochemical stability against Li metal of the high ionic conducting Li3ClO glass. We use the stochastic quenching method based on first principles theory to model the amorphous structure of the glass. We characterise the structure by means of radial distribution functions, angle distributions functions, bond lengths and coordination numbers. Our calculations of the electronic structure of Li3ClO for both phases, crystalline and amorphous, demonstrate that both materials are good insulators. We assess the electrochemical stability of the electrolyte against Li metal electrode and in particular we analyse the role of amorphisation. Our results show that crystalline Li3ClO is not stable against Li metal electrode and that the glass can be made stable if less oxygen is supplied, for instance, by producing an substoichiometric glass.

The hexagonal close-packed (hcp) phase of iron is unstable under ambient conditions. The limited amount of existing experimental data for this system has been obtained by extrapolating the parameters of hcp Fe-Mn alloys to pure Fe. On the theory side, most density functional theory (DFT) studies on hcp Fe have considered non-magnetic or ferromagnetic states, both having limited relevance in view of the current understanding of the system. Here, we investigate the equilibrium properties of paramagnetic hcp Fe using DFT modelling in combination with alloy theory. We show that the theoretical equilibrium c/a and the equation of state of hcp Fe become consistent with the experimental values when the magnetic disorder is properly accounted for. Longitudinal spin fluctuation effects further improve the theoretical description. The present study provides useful data on hcp Fe at ambient and hydrostatic pressure conditions, contributing largely to the development of accurate thermodynamic modelling of Fe-based alloys.

Thermal effects on the elastic and thermodynamic properties of face-centered cubic (fcc) Al-Li and Al-Cr alloys are investigated here by means of density-functional theory. We calculate the polycrystalline Young's modulus, Poisson's ratio, bulk modulus and shear modulus as a function of alloying concentration and temperature. The calculated elastic and thermodynamic properties are in good agreement with available experimental data. Increasing temperature lowers the values of the moduli of both alloys. The results show that both alloying elements increase the Young's modulus. In the case of Al-Li alloys, below 8 at.% Li the Young's modulus increases due to solid solution formation. Further improvement of the stiffness at higher concentrations is due to formation of precipitates. Cr increases almost linearly the Young's modulus, which at 10 at.% Cr becomes almost 34% higher than that of pure Al. The formation of precipitates do not affect the value of the elastic moduli at low Cr concentrations. We estimate the solid solution hardening effect in these alloys by combining the Labusch-Nabarro theory with density-functional theory data.

We employ quantum mechanics modeling to investigate the effects of Ge and Si solute elements on the elastic properties and plastic deformation modes in two families of high-entropy alloys, CoCrFeMnNi and CoCrFeNi, and medium-entropy alloy, CoCrNi. The static lattice constants and single-crystal elastic parameters are calculated for these three face-centered-cubic random solid solutions as a function of composition. Using the elastic constants, we analyzed mechanical stability, derived polycrystalline modulus, and evaluated solid-solution strengthening for these multi-component alloys. We fabricated (CoCrFeNi)(100-x) Si-x (x = 0, 4, 6) and measured the polycrystalline modulus and hardness. The calculated trends for Young's and shear modulus as well as lattice parameters were verified by our measurements. The dependence of generalized stacking fault energy on Ge and Si was studied in detail for the considered multi-component alloys. The competition between various plastic deformation modes was revealed based on effective energy barriers. Our calculations predict that the activated deformation modes in all the alloys studied here are the stacking fault mode (dominant) and the full-slip mode (secondary), and as the concentrations of Ge and Si increase, twining becomes favored.

High-entropy alloys are a new type of materials with excellent properties that offer a great variety of possibilities due to the large degree of freedom in element composition. In particular, CoCrFeNiW alloys have recently attracted a lot of attention due to their potential use in solving the long-standing problem of substituting cobalt in the cemented carbide industry. The lack of experimental and theoretical studies on these multi-components alloys hinders their optimal development. In this work, we aim at filling in this gap by studying their mechanical properties employing first-principles alloy theory and experimental techniques. By using the calculated elastic parameters, we analyzed the mechanical stability, elastic anisotropy, Debye temperature, and derived polycrystalline moduli. Moreover, we fabricated CoCrFeNi and (CoCrFeNi)0.96W0.04 and analyzed them by means of X-ray diffraction and electron backscatter diffraction. The hardness and the Young's modulus were measured. The Young's moduli and the lattice parameters were compared to first principles calculations and good agreement was obtained. Hardness increases with the increment of W composition.

Martensitically formed duplex fcc + hcp Co-based entropic alloys have been investigated both experimentally and theoretically. Theoretical predictions are in good agreement with experimental observations. A fair correlation is found between calculated driving forces for a partitionless fcc→hcp transformation and experimentally obtained phase fractions.