High-entropy alloys (HEAs) possess exceptional mechanical properties and thermal stability, yet their vast compositional space and complex atomic arrangements present significant challenges for property prediction and design. To overcome this, we have trained a machine-learned interatomic potential (MLIP) for the AlTiCrMoW HEA using the message-passing atomic cluster expansion (MACE) framework. This new MLIP is trained on a series of high-accuracy density functional theory (DFT) calculations that covers the available configuration space of the HEA. The training set includes key configurations with linear-response-informed short-range ordered configurations, which are generated using a concentration wave analysis within the coherent potential approximation (CPA) and subsequently optimizedd using conventional DFT calculations. Phonon bispersion ands (PDBs) for the HEA are generated using the MACE model, and several physical properties are extracted for the HEA, such as the elastic constants and the bulk modulus. The fine-tuned model reproduces DFT structural and elastic benchmarks with high accuracy, at a significantly reduced computational cost, allowing for larger simulations to be performed, which can more accurately probe the configuration space and composition of the alloy. Here, we perform Monte Carlo based simulations to identify the ordering transition of equiatomic AlTiCrMoW, where we match the experimental value of 1273 K. Vacancy relaxation volumes are investigated for AlTiCrMoW, as an example of a property analysis, which would be computationally intractable via DFT.

This work describes topological magnon transport in zigzag ${\mathrm{CrI}}_3$ nanoribbons in the presence of edge strain. Exchange coupling terms under strain are obtained from first-principles calculations and the topological properties are introduced via second-neighbor Dzyaloshinskii-Moriya interactions (DMI). The magnon Hamiltonian is calculated using linear spin-wave theory and the Holstein-Primakoff transformation. Then, we use the nonequilibrium Green's function method to calculate the spin-wave-generated currents in ribbons with different edge strain. Our calculations show the formation of strongly localized edge topological magnons within the gap for DMI values slightly higher than the ones reported experimentally and in the presence of a tensile edge strain of the order of 3%. The magnon-mediated topological spin transport calculations show an increase of the spin current and characteristic decay length in tensile-strained ${\mathrm{CrI}}_3$ nanoribbons compared with unstrained ones. Our findings demonstrate that straintronics provides a powerful route to harness and control topological magnons in two-dimensional magnetic materials.

We characterize the magnetic ground state of the newly synthesized lanthanide intermetallic ${\mathrm{GdNiSn}}_4$ via resonant elastic x-ray scattering measurements. This compound forms distorted square nets of Gd that initially order magnetically below 23 K, followed by a lower-temperature transition at 16 K. Our scattering data identify the ground state order as a single-q incommensurate, collinear order that slides towards a commensurate wave vector above the 16 K transition. Magnetic symmetry analysis combined with azimuthal dependence resolves the ground state magnetic structure as a moment-modulated spin density wave state with Gd moments oriented parallel to the in-plane $a$-axis. We discuss connections between the observed magnetic order and electronic properties in this square-net compound.

Cerium hydride has a variety of interesting properties, including a known lattice contraction and densification with increasing hydrogen content. However, precise stoichiometric control is not experimentally straightforward and ab initio approaches are not computationally feasible for many properties such as melting and low temperature diffusion. Therefore, we develop a machine-learned interatomic potential for cerium hydride that is valid for H to Ce ratios from 2.0 to 3.0. A query-by-committee active learning approach is used to develop the training set. Leveraging classical molecular dynamics simulations, we assess a range of properties and provide fundamental mechanisms for the trends with stoichiometry. A majority of the properties follow the trend of lattice contraction, being governed by the stronger lattice binding induced by adding octahedral atoms.

Using liquid-quench reactive force field ReaxFF molecular dynamics, we revisit how changes within the method parameter space—annealing time, annealing temperature, and number of atoms—influence the nanostructure of ${sp}^2$-dominated amorphous carbon at 1 g/cm³ mass density. Initially, the degree of graphitization, measured by the fraction of ${sp}^2$ bonding, increases monotonically with annealing time and temperature. Elevating the annealing temperature above 4000 K disrupts the balance between graphitic ordering and temperature-induced disorder, resulting in detrimental variations in the ${sp}^2$-bonding fractions, ring-size distributions, pore formation, and mass-density uniformity. The widest nanopore-size distribution, extending into the mesopore range, is associated with the maximum graphitization, and is achieved through pore coarsening within the 4000 K annealing window. The system size maintains the robustness of these findings as the larger available volume promotes formation of larger nanopores. The obtained models were subsequently subjected to large uniaxial deformations, where representative 8000 atoms models display only modest residual elastic anisotropy, even in systems with both micro- and mesopores. The initial linear elastic response extends into a nonlinear elastic regime characterized by preservation of original carbon–carbon bonding and pore identity, but with pore stretching and progressive alignment of graphitic layers with the loading direction. At higher strains, heterogeneous ring-size expansion accompanied by ${sp}^2$-chain formation at layer junctions enables extended plastic deformation prior to fracture. The intrinsic pore preservation across a large strain range, high strain tolerance, and gradual failure make microporous amorphous carbon particularly attractive as a durable carbon framework for next-generation ion-based battery electrodes.

The applicability of hybrid density functional approximations (DFAs) in the solid state is still largely hindered by a high computational cost in the evaluation of the exact exchange series. We review formal and computational aspects of a direct space approach to the evaluation of exact exchange in periodic systems with local, atom-centered, Gaussian-type basis functions. We discuss an efficient prescreening strategy in terms of the localized basis to either truncate the series via overlap-based criteria or partition it into distinct regions where the integrals can be computed exactly or approximately via a bipolar expansion of the Coulomb operator. The inclusion of exact exchange in hybrid DFAs largely corrects for the self-interaction error, ensures a better description of electron localization, and thus proves crucial to the characterization of defects, strongly correlated materials, band gaps in semiconductors, as well as to an effective treatment of spin-orbit and electron-phonon couplings. Three test systems are considered, which have been selected as representative of different electronic regimes: (i) bulk hematite, $\alpha \text{−}{\mathrm{Fe}}_2{\mathrm{O}}_3$, in its insulating, antiferromagnetic configuration; (ii) semiconducting single-layer ${\mathrm{WSe}}_2$ (with inclusion of spin-orbit coupling); and (iii) bulk EuO in its metallic ferromagnetic phase at a pressure of 20 GPa. The strategy is assessed on various electronic properties (energy, band gap, spin magnetic moment, Rashba splitting) and is documented to yield calculations with hybrid DFAs with a relative cost of just 3–6 times that of standard (semi)local DFAs.

Direct orientation contrast imaging of zinc-blende III-V materials is studied using scanning electron microscopy. A quantitative approach is taken using a 3 µm thick orientation-patterned GaP grown on a GaAs sample, studying the antiphase domain contrast with respect to the electron beam energy and the tilt angle. A qualitative approach is taken for III-V grown on nonpolar materials with and without chemical mechanical polishing. Finally, a processing of the acquired image for GaP on Si reveals in-plane preferential antiphase boundaries.

Bilayer stacking provides a powerful route to engineer quantum phases in two-dimensional materials. We investigate a bilayer system constructed from monolayers of the BaF electride—a prototypical magnetrene—and find a pronounced tendency toward antiferromagnetic (AFM) ordering driven by interlayer confinement of interstitial anionic electrons. Using first-principles calculations and dynamical mean-field theory (DMFT), we show that the bilayer is dynamically stable and that our density functional theory calculations indicate an AFM-G configuration as the lowest among the collinear magnetic orders examined, with spin density highly localized between the layers. Constructing cavity-centered Wannier functions yields an effective low-energy Hamiltonian for the correlated interstitial subspace. DMFT calculations show that increasing electronic correlations triggers spectral weight transfer to Hubbard bands, leading to quasiparticle suppression and the opening of a correlation-induced gap. Long-lived local moments emerging within the interlayer subspace, signaled by the progressive flattening of $\chi \left(\tau \right)$ with $U$, naturally favor AFM ordering. Our findings establish bilayer electrides as a tunable platform for creating and controlling correlated magnetic states via confinement in a van der Waals gap.

Ionic liquid gating (ILG) technique has been demonstrated as a powerful manner to manipulate the valence-state and electronic structures of complex oxides through topotactic phase transformations. However, the dominant type of transfer ions of a particular system and the underlying mechanisms for the ion incorporation dynamics remain controversies in different systems. In this article, ILG treatments were applied to double-perovskite ${\mathrm{La}}_2{\mathrm{NiMnO}}_6$ (LNMO) system. In response to positively gated electric bias, protons (${\mathrm{H}}^{+}$) incorporate into LNMO films gradually. Based on the combined results from synchrotron-based x-ray absorption and photoelectron spectroscopies, the doped electrons not only induce the valence-state reductions of both Mn and Ni sites, but also the downshift of the valence-band maximum away from the Fermi level, which is distinct from the valence-state and electronic-state variations induced by electron doping from oxygen vacancies (${\mathrm{V}}_{\mathrm{o}}$). This peculiar valence-state reduction has been verified by first-principles calculations, which not only enlightens the roles of energy competitions between ${\mathrm{H}}^{+}$ insertion and ${\mathrm{V}}_{\mathrm{o}}$ formation, but also the electronic structures near the Fermi level in determining the electrochemical gating mechanism of complex oxides.

The crystal and magnetic structures of the nitride antiperovskite $\mathrm{M}{\mathrm{n}}_3\mathrm{GeN}$ reveals ferrimagnetic order stemming from a distorted kagome-derived lattice of the Mn atoms. Polycrystalline $\mathrm{M}{\mathrm{n}}_3\mathrm{GeN}$ was synthesized via a solid-state reaction and characterized using neutron powder diffraction, dc magnetometry, and first-principles calculations. Rietveld refinement reveals near-stoichiometric composition ($\mathrm{M}{\mathrm{n}}_3\mathrm{Ge}{\mathrm{N}}_{0.992\left(7\right)}$) adopting a tetragonal $I4/mcm$ structure at $T=500\mathrm{K}$ and below, featuring axially distorted and tilted $\left[\mathrm{NM}{\mathrm{n}}_6\right]$ octahedra that result in a buckled Mn kagome lattice. On heating, the tetragonal distortion and octahedral tilt angle decrease continuously before transitioning to the cubic $Pm\overline{3}m$ antiperovskite phase at $T\approx 527\mathrm{K}$. Neutron diffraction and magnetometry together reveal noncollinear ferrimagnetic ordering. For $30\mathrm{K}\le T\le 500\mathrm{K}$, the magnetic structure is described by magnetic space group $Ib{a}^{\prime }{m}^{\prime }$ (72.544), with inequivalent Mn1 and Mn2 sublattices that couple antiferromagnetically to yield a net moment. Density-functional theory-based calculations show that the different local moments originate from the bandwidths associated with distinct Mn–N bond lengths. Temperature-dependent refinements reveal distinct differences in the thermal disordering profiles of the Mn1 and Mn2 sublattices. These findings reveal a subtlety in the magnetic and structural behavior of $\mathrm{M}{\mathrm{n}}_3\mathrm{GeN}$, highlighting the interplay between structural distortions, magnetic ordering, and electronic structure in kagome-derived antiperovskite materials.

As a crucial information carrier in condensed matter physics and next-generation information devices, the valley degree of freedom has made the realization of its polarization modulation and effective induction of the anomalous valley Hall effect a core research direction in the field of valleytronics. However, relevant studies on achieving this effect in two-dimensional double-transition-metal MXenes antiferromagnetic systems remain scarce. Based on first-principles calculations, we systematically investigate the valley-related electronic structure and transport properties of double-transition-metal MXene ${\mathrm{HfCr}}_2{\mathrm{C}}_2{\mathrm{H}}_2$. It is found that the ${\mathrm{HfCr}}_2{\mathrm{C}}_2{\mathrm{H}}_2$ can lift the valley degeneracy at the edges of the conduction and valence bands, resulting in valley splittings of 63.3 meV and 16.1 meV, respectively. Importantly, the nonzero Berry curvature in the K and ${\mathrm{K}}^{\prime }$ valleys, together with the finite anomalous Hall conductivity in the vicinity of the band edges, provides evidence for the anomalous Hall effect in the valley in this material. Furthermore, the valley splitting can be effectively tuned by the magnetization direction and biaxial strain, while the valley polarization can be reversed through manipulation of the magnetization direction. This study provides a new material platform and theoretical basis for the design and development of magnetically controlled valleytronic devices in double-transition-metal MXenes.

Noncollinear antiferromagnets exhibit anomalous Hall and magneto-optical Kerr effects driven by Berry curvature despite negligible net magnetization, promising ultrafast spintronic applications. While both effects are theoretically expected to reveal the intrinsic Berry curvature that serves as a spintronic memory bit, their quantitative interpretation is complicated by additional temperature-dependent contributions superimposed on the magnetic order parameter: extrinsic skew scattering in dc Hall transport, and optical-resonance effects in visible-wavelength Kerr measurements. Here we perform polar Kerr measurements at the infrared telecommunication wavelength (1550 nm) on epitaxial, stoichiometric ${\mathrm{Mn}}_3\mathrm{NiN}$ single-crystal films, revealing a spontaneous Kerr signal that remains stable within a few percent over a 200 K range below the Néel temperature. This temperature-invariant intrinsic Kerr response contrasts with the strongly temperature-dependent anomalous Hall effect in the same sample dominated by extrinsic skew scattering. Our findings establish infrared Kerr effect as a robust, local probe of Berry curvature in noncollinear antiferromagnets, enabling quantitative characterization and advancing antiferromagnetic spintronic technologies.

Topologically protected magnetic textures are a promising route to low-energy control of magnetism, but they are most often studied away from ambient conditions, typically at low temperatures and high magnetic fields. Here we use in situ Lorentz transmission electron microscopy with control of temperature and magnetic field to investigate the skyrmion metastability in ${\left({\mathrm{Fe}}_{0.5}{\mathrm{Co}}_{0.5}\right)}_5{\mathrm{GeTe}}_2$ (FCGT). By field-cooling FCGT in magnetic fields of different magnitude to different base temperatures and then removing the applied field, we create meta(stable) zero-field magnetic states. We use this method to build a phase diagram of the zero-field metastable spin structures in FCGT, which will be critical for selecting the desired topologically protected spin state for future studies to manipulate magnetism with stimuli such as electric current, electric field, mechanical strain, and more.

Photonic materials with a prescribed response over multiple spectral bands are essential to applications such as energy harvesting and thermal management. Engineering the response over such a wide range of wavelengths is difficult because these materials have hierarchical structures, which make it challenging to predict and optimize the spectral response. To address this challenge, we develop and compare several optical models aimed at capturing multiscale effects, and we apply these models to understanding the response of microgeodes—dielectric microshells encapsulating nanowires. Among the models, we find that an intensity-based transfer matrix method, newly developed in this work, provides the best agreement with experimentally observed spectra. In particular, it substantially improves the prediction of reflectance at short wavelengths, where the other models significantly underestimate the experimental values, resulting in an overall improvement across the full spectrum. We show that this model has superior predictive performance because it accounts for the interdependent scattering contributions from nanowires and microshells, while circumventing the need to specify reflectance conditions at the boundaries of the microgeode film. This approach could be used to explore the large design space of possible structures in microgeodes and other hierarchically structured, broad-spectrum materials.

Machine-learning interatomic potentials (MLIPs) with broad chemical flexibility are essential for atomistic simulations of compositionally complex alloys, but their deployment in large-scale molecular dynamics requires a balance among accuracy, efficiency, stability, transferability, and uncertainty quantification. Here, we benchmark two chemically scalable MLIP frameworks, neuroevolution potential (NEP) and graph atomic cluster expansion (GRACE), for 16 elemental metals and their multicomponent alloys. GRACE-FS shows higher training efficiency and generally better average accuracy, chemical transferability, and finite-temperature robustness, whereas UNEP-v1 provides substantially higher inference speed and remains competitive in selected stress and large-error metrics. We further show that chemical transferability is closely linked to high-temperature MD stability in highly multicomponent environments and that ensemble-based uncertainty provides a more reliable error indicator than D-optimality for the heterogeneous systems considered here. Finally, $3\times {10}^6$-atom shock simulations demonstrate that UNEP-v1, combined with ensemble uncertainty, enables uncertainty-aware simulations under extreme dynamic conditions, yielding robust global spall-strength predictions while revealing model sensitivity in local damage pathways. These results provide practical guidelines for selecting and deploying MLIPs in large-scale simulations of multicomponent alloys.

Recently, ${\mathrm{NiTe}}_2$ has emerged as a representative metallic transition-metal dichalcogenide (TMD), owing to its tunable electronic transport, high current-carrying capability, and experimental accessibility. However, its phonon transport behavior remains unclear. Here, we employ first-principles calculations to investigate the lattice thermal conductivity ($k_{\mathrm{p}}$) of both 1T and 1H phases for ${\mathrm{NiTe}}_2$. Our results show that in 1T phase, four-phonon (4ph) processes reduce $k_{\mathrm{p}}$ by up to 58.2%, lowering $k_{\mathrm{p}}$ from 3.79/4.69 to 1.70/1.96 W ${\mathrm{m}}^{-1} {\mathrm{K}}^{-1}$ along the armchair/zigzag directions. Electron-phonon interaction (EPI) leads to an additional maximum 29.5% suppression, reducing $k_{\mathrm{p}}$ to 0.58 W ${\mathrm{m}}^{-1} {\mathrm{K}}^{-1}$ at a carrier concentration of 1 × ${10}^{14} {\mathrm{cm}}^{-2}$ in $n$-type 1T-${\mathrm{NiTe}}_2$. In contrast, the 1H phase exhibits a more moderate decrease, with $k_{\mathrm{p}}$ reduced from 3.61 to 2.44 W ${\mathrm{m}}^{-1} {\mathrm{K}}^{-1}$ by 4ph scattering. The most distinct EPI effect in 1H-${\mathrm{NiTe}}_2$ occurs in the intrinsic state, further reducing $k_{\mathrm{p}}$ to 1.57 W ${\mathrm{m}}^{-1} {\mathrm{K}}^{-1}$. The more pronounced suppression in $k_{\mathrm{p}}$ in 1T-${\mathrm{NiTe}}_2$ originates from the larger phonon band gap and higher electronic density of states compared with 1H-${\mathrm{NiTe}}_2$. Our results suggest viable routes to tune phonon transport in TMDs via phase control and carrier engineering.

Understanding the structural origins of thermal expansion in metallic glasses (MGs) is essential for engineering next-generation materials with high thermal stability and performance. Accordingly, we used molecular dynamics simulations to investigate how local atomic motifs control the thermal expansion of MGs. Motif-resolved analysis using Voronoi tessellation reveals that mixed polyhedra are the main contributors to macroscopic thermal expansion, whereas icosahedral units act as stabilizers that resist volume changes. This interpretation is supported by motif-resolved potential-energy analysis, which shows lower, more temperature-stable energies for icosahedral polyhedra, in contrast to the strongly anharmonic response of mixed polyhedra. To connect motif-level thermal expansion to atomic-scale behavior, we analyzed bonds using the radial probability function $\left[G\right(r\left)\right]$. A skewed-normal fit to the first peak shows a monotonic increase in mean interatomic distance with temperature, resolving the apparent contraction reported in earlier studies relying solely on the position of the first peak of $G\left(r\right)$. Overall, this work establishes a coherent structural picture for thermal expansion in MGs. The consistent behavior across the investigated alloys demonstrates that icosahedral units are systematically associated with lower local expansion, while mixed polyhedra dominate the macroscopic thermal response. This motif-dependent behavior is robust across different compositions, interatomic potentials, and cooling rates, providing a basis for designing MGs with improved thermal stability.

The monolayer FeSe film grown on ${\mathrm{SrTiO}}_3$ has attracted tremendous interest due to its remarkable interface-enhanced high-temperature superconductivity and emergent quantum phenomena. However, achieving controlled growth of monolayer FeSe on the ${\mathrm{SrTiO}}_3$ substrate remains challenging. Here, utilizing an in situ molecular beam epitaxy-scanning tunneling microscopy and spectroscopy combined system, we develop a method to successfully grow monolayer FeSe films on both conductive and insulating ${\mathrm{SrTiO}}_3$ substrates through a two-step deposition approach that involves the deposition of Fe clusters and subsequent selenization. By applying postannealing, we further tune the crystallinity and superconducting properties of the as-grown film, yielding an in situ scanning tunneling spectroscopy gap of ∼15.7 meV and an ex situ macroscopic transition temperature of ∼37.2 K. This work provides a valuable route for the controlled growth of interface-enhanced high-temperature superconductors and could be branched out into growing other similar compound films.