Transition-metal dichalcogenides have attracted a great deal of attention in the context of two-dimensional materials because of their electronic properties, derived from their layered crystal structures, as well as their exfoliability. Surprisingly, the combination of high pressure and high temperature has been rarely exploited in the study of these systems, although it is expected to be an efficient way of inducing the formation of novel polymorphs. Here, rhenium and carbon disulfide were observed to react at a pressure of 54 GPa in a laser-heated diamond anvil cell to form a hitherto unknown polymorph of rhenium disulfide, denoted as $mP12\text{−}{\mathrm{ReS}}_2$ in the Pearson notation. Its crystal structure was solved and refined using synchrotron single-crystal x-ray diffraction data, revealing that $mP12\text{−}{\mathrm{ReS}}_2$ adopts the arsenopyrite structure type (space group $P{2}_1/c$). The structure is characterized by an extended three-dimensional framework of corner- and edge-sharing distorted ${\mathrm{ReS}}_6$ octahedra. Raman spectroscopy data further confirm the formation and structure of $mP12\text{−}{\mathrm{ReS}}_2$. Remarkably, upon decompression, $mP12\text{−}{\mathrm{ReS}}_2$ was recovered to ambient conditions and found to be stable in air. Thermodynamic, electronic, and bonding properties of the new phase were also studied computationally within the framework of density functional theory. From these, $mP12\text{−}{\mathrm{ReS}}_2$ is found to be semimetallic at 0 GPa, and to have a lower enthalpy than the previously known ${\mathrm{ReS}}_2$ polymorph from $\sim 0.5\mathrm{GPa}$ onwards. The discovery of this new compound warrants further investigations of its physical properties, and may open new possibilities for applications.

We report experimental and theoretical investigations on the quaternary Heusler alloy CoRuTiGe, synthesized using the arc melting technique. Crystal structure analysis reveals a tetragonal structure at room temperature. Magnetization measurements as a function of temperature and magnetic field indicate a ferromagnetic nature with a saturation magnetization of $\sim 0.681{\mu }_{\mathrm{B}}/\mathrm{f}.\mathrm{u}.$ at 5 K. The temperature dependence of electrical resistivity shows a nearly linear decrease in the high-temperature range, indicating the spin gapless semiconductor (SGS) like behavior of the material. This SGS nature is further supported by the weak temperature-dependent carrier concentration and mobility. Hall effect analysis reveals that the anomalous Hall effect in CoRuTiGe arises from both intrinsic and extrinsic mechanisms. Additionally, a well-defined symmetric negative magnetoresistance is observed at low temperatures. These results offer insights that could aid in designing new spin gapless semiconductors with enhanced Curie temperatures for spintronic applications.

In typical rare-earth lanthanide compounds, the localized $4f$ electrons have a weak effect on the electrical conduction, limiting their influence on the Berry curvature and, hence, the intrinsic anomalous Hall effect. A comprehensive study of the magnetic, thermodynamic, and transport properties of single-crystalline NdGaSi, guided by first‐principles calculations, reveals a ferromagnetic ground state that induces a splitting of quasiflat $4f$ electronic bands and positions them near the Fermi energy. The observation of an extraordinarily large intrinsic anomalous Hall conductivity of $1165{\mathrm{\Omega }}^{-1}{\mathrm{cm}}^{-1}$ implies the direct involvement of localized states in the generation of nontrivial band crossings around the Fermi energy. The angle-resolved photoemission spectroscopy measurements provide direct evidence of nontrivial crossing of the $4f$ bands with dispersive bands. These results are remarkable when compared to ferrimagnetic NdAlSi, which differs only in a nonmagnetic atom (a change in the principal quantum number $n$ of the outer $p$ orbital) with the same number of valence electrons and does not exhibit any measurable anomalous Hall conductivity.

Using first-principles calculations, we study the electronic structure of an unexplored Zintl compound, KCdBi. Our calculations establish KCdBi to be a rare example of a strong $Z_2$ topological semimetal. The compound is found to be cleavable with a small cleavage energy ($\sim 0.2\mathrm{J}/{\mathrm{m}}^2$). The nanostructured KCdBi obtained by cleaving turned out to be a topological insulator, causing a semimetal to insulator transition upon dimensionality reduction. A rich phase diagram emerges upon application of an electric field to nanostructured KCdBi, which consists of topological insulating, $Z_2$ topological metallic, weak and strong Rashba phases. This compound thus offers a platform to study nontrivial properties tunable by electric field and dimensionality. Our findings are expected to stimulate experimental investigation of this interesting compound.

Two-dimensional (2D) magnetic materials have attracted significant attention due to their unique properties and potential applications in spintronics. Using first-principles calculations and group theory analysis, we propose a novel two-dimensional chiral magnetic semiconductor ${\mathrm{FeZrCl}}_6$. The monolayer (ML) ${\mathrm{FeZrCl}}_6$ is dynamically stable and hosts a coplanar noncollinear 120° antiferromagnetic ground state on a triangular lattice, characterized by vector-spin chirality. The group theory analysis reveals that this unique magnetic order activates the anomalous Hall effect (AHE) and magneto-optical Kerr effect (MOKE). During collective in-plane spin rotation, both the AHC and Kerr rotation angle exhibit $2\pi /3$ periodicity dependence on the azimuthal angle $\phi$. Furthermore, out-of-plane spin canting generates a finite scalar-spin chirality, producing an emergent real space Berry phase and thereby inducing a chirality-driven topological Hall effect (THE) and topological magneto-optical Kerr effect (TMOKE) without spin-orbit coupling. These findings not only identify a promising material candidate for antiferromagnetic spintronics but also provide profound insights into the antiferromagnetic anomalous transport phenomena.

Heterostructures that involve contacting magnetic and dielectric layers may possess a voltage-controlled magnetic anisotropy (VCMA) of interfacial origin. In such heterostructures, spin dynamics can be excited by an electric field created in the dielectric layer, which provides an opportunity for the development of energy-efficient spintronic and magnonic devices. Here, we theoretically describe the generation of spin waves by an electric-field-induced modulation of the interfacial magnetic anisotropy in antiferromagnet-dielectric bilayers. Our approach is based on atomistic simulations of VCMA-driven spin reorientations, which are performed for the (001)-oriented FeRh and ${\mathrm{Mn}}_2\mathrm{Au}$ films. It is shown that the sinusoidal variation of VCMA gives rise to the steady precession of spins adjacent to the interface, which induces either evanescent or propagating monochromatic spin waves in the antiferromagnetic film. The amplitude of the generated spin wave strongly depends on the frequency of VCMA oscillations, being maximal at about 33 GHz in the FeRh film and 0.9 THz in the ${\mathrm{Mn}}_2\mathrm{Au}$ one. The analysis of simulation data enables us to determine dispersion relations of the propagating spin waves and their decay lengths. Importantly, antiferromagnetic magnons with high frequencies ∼100 GHz and large decay lengths ∼300 nm can be excited in the FeRh/MgO bilayers. Our findings show that the antiferromagnet-dielectric heterostructures possessing VCMA provide the opportunity for an energy-efficient electrical generation of high-frequency spin waves.

First-order magnetoelastic transitions usually involve mechanisms unique to each family of materials. For ${\left(\mathrm{Mn},\mathrm{Fe}\right)}_2\left(\mathrm{P},\mathrm{Si}\right)$ compounds, it is generally predicted that the unit cell distortion occurring at the ferromagnetic transition leads to a strong electronic reconstruction of the Fe $d$ states accompanied by a notable change in magnetic moment. However, there is no experimental consensus on this mechanism. Here, we use x-ray emission spectroscopy (XES) complemented by first-principles calculations, high-energy resolution fluorescence detected x-ray absorption (HERFD-XAS), and resonant inelastic x-ray scattering (RIXS) experiments, to clarify the nature of the first-order transition in a ${\mathrm{Mn}}_{0.74}{\mathrm{Fe}}_{1.23}{\mathrm{P}}_{0.71}{\mathrm{Si}}_{0.32}$ crystal. HERFD-XAS and RIXS data show a minor evolution of the spectral features in the upper part of the $K$-edge for Mn and Fe, consistent with the calculated $4p$ density of states and fingerprinting the transition. In contrast, no significant evolution of the XES spectra is observed when the transition is crossed. In Fe-rich compositions, the calculations indicate that Fe at the $3g$ site develops a magnetic moment (2.43 ${\mu }_B$) that is smaller than that of Mn at the $3g$ site (2.93 ${\mu }_B$), but larger than that of Fe at the $3f$ site (1.48 ${\mu }_B$). Quantitative XES analysis using the IAD method gives a reasonable agreement with the magnetic moments for different ${\left(\mathrm{Mn},\mathrm{Fe}\right)}_2\left(\mathrm{P},\mathrm{Si}\right)$ compositions. However, the reduction of the Fe moment predicted by theory (approx. $-0.6{\mu }_B$) is not observed around the transition. This study indicates that the Fe moment collapse at the transition may be weaker than the theoretically predicted value or more gradual in temperature, suggesting a secondary role for this moment instability in the giant magnetocaloric effect of ${\left(\mathrm{Mn},\mathrm{Fe}\right)}_2\left(\mathrm{P},\mathrm{Si}\right)$ compounds.

Topological effects arising from the Berry curvature lead to intriguing transport signatures in quantum materials. Two such phenomena are the chiral anomaly and nonlinear Hall effect (NLHE). A unified description of these transport regimes requires a quantitative treatment of both band topology and electron scattering. Here, we show accurate predictions of the magnetoresistance in topological semimetals and NLHE in noncentrosymmetric materials by solving the Boltzmann transport equation with electron-phonon ($e$-ph) scattering and Berry curvature computed from first principles. We apply our method to study magnetotransport in a prototypical Weyl semimetal, TaAs, and the NLHE in strained monolayer ${\mathrm{WSe}}_2$, bilayer ${\mathrm{WTe}}_2$, and bulk ${\mathrm{BaMnSb}}_2$. In TaAs, we find a chiral contribution to the magnetoconductance that is positive and increases with magnetic field, consistent with experiments. We show that $e$-ph interactions can significantly modify the Berry curvature dipole and its dependence on temperature and Fermi level, highlighting the interplay of band topology and electronic interactions in nonlinear transport. The computed nonlinear Hall response in ${\mathrm{BaMnSb}}_2$ is in agreement with experiments. By adding the Berry curvature to first-principles transport calculations, our work advances the quantitative analysis of a wide range of linear and nonlinear transport phenomena in quantum materials.

The accuracy of microstructure-based modeling in predicting the mechanical response of particle reinforced aluminum matrix (${\mathrm{SiC}}_{\mathrm{p}}$/Al) composites is primarily determined by the validation of material constitutive parameters. Therefore, the constitutive parameter calibration process and synergistic mechanism of multiphase damage under uniaxial tensile loading in 35 vol.% ${\mathrm{SiC}}_{\mathrm{p}}$/Al composites were systematically investigated through a combined experimental characterization and microstructure-based modeling. Dual-scenarios microstructure-based models of ${\mathrm{SiC}}_{\mathrm{p}}$/Al composites for nanoindentation and uniaxial tension simulations were established based on quantitative morphological statistics obtained from scanning electron microscopy. By integrating linear array nanoindentation testing with microstructure-based inverse finite element analysis, the constitutive parameters for both the matrix and interfacial phases were successfully calibrated, which were subsequently validated through representative volume element (RVE) model for uniaxial tension simulations and experimental verification. Numerical simulations revealed two key findings: (1) The relative accuracy of the elastic modulus in the parameter-calibrated RVE model increased from 38.68% to 87.99% compared to the precalibrated model, while the relative accuracy of tensile strength improved from 81.13% to 98.73%. (2) During damage evolution, initial damage nucleation occurred at particle sharp corner interfaces. Subsequently, cross-phase coupling between matrix shear-induced localized bands and interfacial cracks formed macroscopic fracture bands.

Since the advent of scanning probe microscopy, elemental- and chemical discrimination on heterogeneous surfaces has been a major challenge. This is mainly due to complex contrast mechanisms, which require considerable indirect structural assumptions of tip and surface and related extensive theoretical modeling. Previously, noncontact atomic force microscopy with atomically defined copper oxide tips (CuOx-tips) showed elemental selectivity on even most complex metal-oxide surfaces [Hütner et al., Science 385, 1241, 2024]. Here we report an investigation of an ionic surface, which allows to directly identify the anionic- and cationic sub lattices even on aperiodic surface structures. In line with previous work on metal oxides [Wiesener et al., ACS Nano 18, 21948, 2024], the present results extend chemically selective imaging of CuOx-tips to a new class of heterogeneous materials.

We develop a conserving Keldysh field theory for a moving dislocation represented by a discrete Kanzaki force and coupled to electronic and phononic baths. Within this framework the configurational electron wind force and the electronic drag emerge as the odd and even components of a single retarded stress correlation kernel constructed from the same deformation potential vertex, placing both mechanisms on the same many-body footing as standard transport coefficients. Symmetry of the slip geometry enforces a shear channel theorem in which electronic drag couples only to shear stress, while the electron wind is polar with respect to the Burgers vector, providing a microscopic mechanism for current-induced texture evolution. The formalism yields closed expressions for electronic drag and electron wind in terms of Fermi surface averages of deformation potentials, band velocities, and the screened Kanzaki projector, with no phenomenological relaxation times or adjustable masses. Evaluated from first principles for edge dislocations in face-centered cubic Al and basal dislocations in hexagonal close-packed Zn, these expressions give electronic drag coefficients that are several orders of magnitude smaller than phonon drag throughout the experimentally relevant temperature range, whereas the electron wind produces configurational stresses of order megapascals at current densities $J\sim {10}^8\text{–}{10}^9\mathrm{A}{\mathrm{m}}^{-2}$, consistent with reported electroplastic softening. Extension to finite magnetic field predicts a magnetoplastic analog of magnetoresistance, in which the drag is suppressed by cyclotron deflection while the wind remains essentially field independent. The theory therefore converts wind and drag from phenomenological fit parameters into parameter free functionals of the electronic structure and provides a direct route from electronic structure calculations to dislocation mobility laws in electroplastic and magnetoplastic flow.

The layered rare-earth diantimonides, $R{\mathrm{Sb}}_2$, ($R$ = lanthanide element) composed of Sb square-net sheets exhibit diverse structural phases with distinct stacking configurations which can be tuned by the growth temperature, stoichiometry, and pressure. The recent discovery by Llanos et al. [Nano Lett. 24, 8518 (2024)] of a novel monoclinic polymorph of ${\mathrm{LaSb}}_2$ raises the important question as to why ${\mathrm{LaSb}}_2$ has been synthesized in the orthorhombic phase in previous experimental studies. We have employed first-principles electronic structure calculations to investigate the effect of charge doping and phonon entropy on the relative stability between four competing structural phases of ${\mathrm{LaSb}}_2$: the ${\mathrm{SmSb}}_2$-type, the ${\mathrm{YbSb}}_2$-type, the MBE-grown monoclinic, and our novel theoretically predicted orthorhombic structures (space group No. 58, $Pnnm$). The calculations reveal that the ${\mathrm{SmSb}}_2$-type orthorhombic phase is stabilized by electron doping that can presumably occur during bulk growth conditions such as Sb-rich flux, intrinsic vacancy formation, etc. However, the phonon entropy is found to reduce the free energy of the monoclinic phase faster than that of the orthorhombic phase with increasing temperature, indicating that the monoclinic phase becomes more stable at high temperatures. We also present the dynamical instabilities in two well-known structures with or without strain that qualitatively explain the pressure-dependent charge density waves of ${\mathrm{LaSb}}_2$. This research aims to shed light on the microscopic mechanisms underlying the complex and competing structural phases and resulting transitions in the family of $R{\mathrm{Sb}}_2$ systems.

Electron-irradiation induced creep rates in amorphous alloys, a-${\mathrm{SiO}}_2, {\mathrm{Fe}}_{79}{\mathrm{B}}_{16}{\mathrm{Si}}_5, {\mathrm{Cu}}_{60}{\mathrm{Ta}}_{40}$, and ${\mathrm{Cu}}_{50}{\mathrm{Ti}}_{50}$, were measured at room temperature using a miniaturized beam-bending apparatus within a transmission electron microscope operated at 200 keV. The creep rates of these amorphous samples increased nearly linearly with both e-beam current density and applied stress, while a reference crystalline (c-)${\mathrm{SiO}}_2$ sample failed to creep under the same conditions. The irradiation-induced creep compliance of a-${\mathrm{SiO}}_2$ was $\sim 15$ times larger than that of ${\mathrm{Fe}}_{79}{\mathrm{B}}_{16}{\mathrm{Si}}_5$ and over 1,000 times larger than that of the two Cu alloys. Molecular dynamics computer simulations were employed to simulate electron irradiation induced creep using interatomic potentials representing amorphous ${\mathrm{Cu}}_{75}{\mathrm{Zr}}_{25}, {\mathrm{Ni}}_{85}{\mathrm{P}}_{15}$, and ${\mathrm{SiO}}_2$ as model systems. The irradiation induced creep compliances calculated for ${\mathrm{Cu}}_{75}{\mathrm{Zr}}_{25}$ during 200 keV electron irradiation provided good quantitative agreement with the two Cu-based alloys, but that for a-${\mathrm{SiO}}_2$ was $\sim 180$ times too small. These results indicate that unlike neutron or ion-beam induced creep in a-${\mathrm{SiO}}_2$, creep under electron irradiation is dominated by the effects of ionization, owing largely to the far higher ratio of electronic stopping to nuclear stopping for electrons than for ions.

Defect engineering and functionalization enable the precise modulation of a material's local reactivity, electronic doping, and optical response. Motivated by its promising optical and excitonic characteristics, we show that the electronic properties of the 2H-phase ${\mathrm{TiBr}}_2$ monolayer can be effectively tuned via vacancy engineering and adatom functionalization, thereby unlocking potential applications in catalysis, sensing, and optoelectronic devices. Herein, using density functional theory (DFT), we investigate pristine (${\mathrm{TiBr}}_2^{\text{pri}}$) and its modified monolayers by including vacancies Br-type (${\mathrm{TiBr}}_2^{\text{vac}}$), as well as those functionalized by common atomic adsorbates (X = H, C, N, and O, denoted as $\mathrm{X}/{\mathrm{TiBr}}_2$). For the pristine surface, all adatoms exhibit weak physisorption, with adsorption energies $|E_{\text{ads}}| < 1\mathrm{e}\mathrm{V}$. In contrast, the introduction of Br vacancies dramatically enhances the surface reactivity, resulting in strong chemisorption at the vacancy sites (for all adatoms) with large adsorption energies and substantial electronic modifications. The present work provides a comprehensive energetic decomposition framework (adsorption, interaction, and distortion energies) applied to transition-metal dihalide monolayers. We expect that similar defect- and adatom-induced reactivity may emerge in structurally related 2D transition-metal halides. In addition, our findings demonstrate that the electronic and adsorptive properties of ${\mathrm{TiBr}}_2$ monolayers can be rationally engineered through defect and adatom manipulation.

Lattice vacancy migration barriers in ferromagnetic ${\mathrm{Fe}}_x{\mathrm{Ni}}_{1-x}$ alloys ($0.4\le x\le 0.6$) are accurately quantified within the framework of ab initio electronic structure calculations using the nudged elastic band (NEB) method. Both the atomically disordered (A1) fcc phase, as well as the atomically ordered, tetragonal $\mathrm{L}{1}_0$ phase—which is under consideration as a material for a rare-earth-free gap magnet for advanced engineering applications—are investigated. Across an ensemble of NEB calculations performed on supercell configurations spanning a range of compositions and containing disordered, partially ordered, and fully ordered structures, we find that Ni-vacancy interchanges encounter significantly higher energetic barriers than do Fe-vacancy interchanges. We contend that this aspect is a key factor in determining the differences in mobility between Fe and Ni atoms in this ferromagnetic alloy. Moreover, we are able to interpret these findings in terms of the ferromagnetic alloy's underlying spin-polarized electronic structure. Specifically, we report a coupling between the size of local lattice distortions and the magnitude of the local electronic spin polarization around vacancies. This causes Fe atoms to relax into lattice vacancies, while Ni atoms remain rigidly fixed to their original lattice positions. These results give atomic-scale insight into the longstanding experimental observation that Ni exhibits remarkably slow atomic diffusion in Fe-Ni alloys.