While bulk bcc plasticity is traditionally governed by screw dislocation glide, prismatic dislocation loops are proposed as an essential pathway for strain accommodation under severe, local constraints. This experimental study on pure W, as a model bcc system, demonstrates that prismatic dislocation half-loops can develop and propagate in a triaxial stress field as imposed by nanoindentation. Using electron channeling contrast imaging, the Burgers vector of emitted dislocation half-loops is determined to be 1/2 $\langle 111\rangle$ and the punching-out process is studied during progressive stages of imposed strain. Long arrays of dislocation half-loops are emitted during the initial displacement burst (pop-in) and continue to propagate during subsequent loading. Although energetic considerations indicate that loop formation alone cannot account for the total plastic deformation energy—implying a concurrent contribution from glide mechanisms—these findings reveal that plastic flow under severe hydrostatic stress gradients can be accommodated via non-Schmid loop punching. Crucially, the unique slip system multiplicity of the bcc lattice yields highly mobile, circular loop geometries that stand in stark contrast to the faceted loops typical of fcc metals.

Interpretable AI can reveal physical principles governing intricate materials properties by uncovering explicit relationships between physical parameters and target properties. The sure-independence screening and sparsifying operator (SISSO) symbolic regression approach identifies analytical expressions that correlate a target property with a small set of parameters, termed materials genes, selected from a large pool of candidates. However, multiple gene combinations can yield equally accurate SISSO models, with individual genes contributing with different weights. Here, we establish a derivative-based sensitivity analysis that enhances interpretability, thereby enabling deeper physical insight. This analysis also reveals how distinct gene combinations encode equivalent information and identifies valence orbital radii, nuclear charges, and their products as the key quantities governing the equilibrium lattice constant of perovskites.

We investigate the spin Hall effect (SHE) in a van der Waals (vdW) ferromagnet ${\mathrm{Fe}}_5{\mathrm{GeTe}}_2$ (FGT) with a Curie temperature $T_{\mathrm{C}}$ of 310 K utilizing the spin-torque ferromagnetic resonance method. In synchronization with the emergence of the ferromagnetic phase resulting in the anomalous Hall effect (AHE), a noticeable enhancement in the SHE was observed below $T_{\mathrm{C}}$. On the other hand, the SHE shows a different temperature dependence from the AHE: the effective spin Hall conductivity is clearly enhanced with decreasing temperature unlike the anomalous Hall conductivity, reflecting the variation in the band structure accompanied by the complicated magnetic ordering of the FGT. The results provide a deep understanding of the SHE in magnetic materials to open a new route for novel functionalities in vdW materials-based spintronic devices.

Giant responses over wide temperature ranges in relaxor ferroelectrics remain a puzzling phenomenon in solid state physics. Rapid-quenching x-ray diffraction demonstrates pronounced kinetic suppression of macroscopic structural ordering in ($1-x$)Pb(${\mathrm{Mg}}_{1/3}{\mathrm{Nb}}_{2/3}$)${\mathrm{O}}_3\text{−}x{\mathrm{PbTiO}}_3$ near the morphotropic phase boundary. Independently, neutron scattering reveals scale-free spatial and temporal correlations of polar nanoregions over the temperature range associated with the giant dielectric response. Taken together, these observations support a kinetic picture in which sluggish structural ordering allows near-critical relaxor fluctuations to persist over an extended temperature range.

Machine learning interatomic potentials (MLIPs) are routinely used to model diverse atomistic phenomena, yet parameterizing them to accurately capture solid-state phase transformations remains difficult. We present error metrics and data-generation schemes designed to streamline the parameterization of MLIPs for modeling precipitation in multicomponent alloys. We developed an algorithm that enumerates symmetrically distinct transformation pathways connecting chemical decorations of different parent crystal structures. Additionally, we introduce the weighted Kendall-$\tau$ coefficient and its semigrand-canonical generalization as metrics for quantifying MLIP accuracy in predicting low-temperature thermodynamics. We apply these approaches to parameterize an MLIP for a dilute Mg–Nd alloy. The resulting potential reproduces the complex early stage precipitation behavior observed experimentally. Large-scale atomistic simulations reveal competition between order-disorder and structural transformations. Furthermore, these results suggest a continuous transition between high-symmetry hcp and bcc crystal structures during aging heat treatments.

We report a comparative neutron single crystal diffraction study of the structural and magnetic properties of layered halides ${\mathrm{CrCl}}_3$ and $\alpha \text{−}{\mathrm{RuCl}}_3$. They host a honeycomb arrangement of transition metal ions with distinct electronic configurations and undergo a first-order structural transition between high-temperature $C2/m$ and low-temperature $R\overline{3}$. Both compounds show a step-like change in the $c$-lattice parameter across the structure transition. In contrast, the in-plane lattice response is quite different: $\alpha \text{−}{\mathrm{RuCl}}_3$ exhibits an abrupt hysteretic change across the transition accompanied by progressive crystalline degradation upon thermal cycling, whereas ${\mathrm{CrCl}}_3$ shows a smooth in-plane lattice evolution and remains structurally robust. Magnetically, ${\mathrm{CrCl}}_3$ orders into an A-type antiferromagnetic structure at $T_N=14$ K and exhibits pronounced diffuse magnetic scattering extending up to about 40 K. $\alpha \text{−}{\mathrm{RuCl}}_3$ shows no observable magnetic diffuse scattering above its zigzag antiferromagnetic ordering temperature $T_N=7.6$ K. These results suggest that the contrasting structural responses arise from an interplay between interlayer sliding energetics, stacking-strain coupling, and elastic accommodation of the stacking transition. The distinct chemical bonding and electronic configurations of the two compounds provide a microscopic basis for their different lattice responses to the structure transition and magnetic correlations.

Element-specific magnetism at the atomic scale is important in low-dimensional materials such as thin magnetic films and quantum dots, where interfacial and surface effects can give rise to novel behavior. However, probing magnetism specific to the topmost atomic layer remains a key experimental challenge. Here, we introduce a synchrotron x-ray scanning tunneling spectroscopy approach that enables detection and quantification of surface magnetism via x-ray-excited electron tunneling. By illuminating a scanning tunneling microscope tip-sample junction with circularly polarized x-rays tuned to the Ni $L_{2,3}$ absorption edges, ensemble-averaged and surface atomic-layer x-ray magnetic circular dichroism are simultaneously measured on a $\sim 2.5$-monolayer-thick Ni film grown on a Cu(111) surface. Measurements are performed at substrate temperatures of 90 and 22 K. The results reveal enhanced orbital and spin magnetic moments in the outermost atomic layer as compared to the ensemble-averaged moments of the thin Ni film at both temperatures. This work establishes an experimental method for quantitative, element-specific magnetometry with atomic-layer sensitivity using x-rays.

Negatively charged nitrogen-vacancy $\left({\mathrm{NV}}^{-}\right)$ centers located a few nanometers below the diamond surface are key quantum defects for nanoscale sensing of external spins. However, the creation of shallow ${\mathrm{NV}}^{-}$ centers with high yield remains a materials challenge. Here, we demonstrate that high-angle ion implantation enhances the creation efficiency of shallow ${\mathrm{NV}}^{-}$ centers. By implanting ${}^{15}\mathrm{N}$ ions at angles exceeding ${60}^{\circ }$, we achieve high ${\mathrm{NV}}^{-}$ yields approaching 10% with effective ${\mathrm{NV}}^{-}$ depths below 10 nm. These yields are significantly higher than those typically reported for shallow ${\mathrm{NV}}^{-}$ creation. The enhanced ${\mathrm{NV}}^{-}$ yield is consistent with an increased vacancy-to-nitrogen ratio in the near-surface region, which is expected to promote NV formation during annealing. The created ${\mathrm{NV}}^{-}$ ensembles show coherence properties comparable to those of single shallow ${\mathrm{NV}}^{-}$ centers at similar depths, and allow detection of nuclear spins in van der Waals materials attached to the diamond surface. Our results establish geometric control of ion implantation as a simple and broadly applicable approach to engineer shallow vacancy-related quantum defects.

Bi is predicted to be an efficient generator of spin–orbit torques (SOTs), with charge-to-spin conversion efficiency comparable to those of prototypical heavy metals, such as Ta, W, and Pt. However, experimental reports provide widely scattered interconversion efficiencies, while the origin of the large conversion signal in Bi/Ag bilayers remains controversial. Here, we investigate charge-to-spin conversion in epitaxial and polycrystalline Bi-based magnetic heterostructures by measuring the damping-like SOT using magneto-optic Kerr effect magnetometry, complemented by structural and spectroscopic analyses and comparison with harmonic Hall resistance measurements. We show that inserting an Ag spacer between Bi(001) and metallic ferromagnets (FeCo or Ni) enhances the SOT efficiency by more than one order of magnitude, reaching an effective spin Hall conductivity of approximately $2\times {10}^5(\hslash /2e)\mathrm{S}/\mathrm{m}$, in excellent agreement with theoretical expectations for bulk Bi. This enhancement can be consistently explained by the preservation of the structural and chemical integrity of Bi—otherwise compromised by the direct deposition of a ferromagnetic overlayer—rather than by Rashba spin–orbit coupling at the Bi/Ag interface. We show that Ag forms an atomically sharp, chemically inert interface with Bi that, unlike other metallic spacers such as Al and Cu, prevents interdiffusion and solid-state dewetting while enabling efficient charge-to-spin conversion. Angle-resolved photoemission spectroscopy reveals no measurable enhancement of the Rashba spin splitting at the Bi(001) surface upon Ag deposition. Comparative studies across epitaxial, polycrystalline, and intentionally surface-oxidized Bi films, beyond oxygen doses known to destroy Bi(001) surface states, reveal that structural disorder has a negative impact on the SOT efficiency. Meanwhile, the retention of 72% of the SOT efficiency following oxygen exposure indicates a dominant bulk contribution to spin-current generation in Bi/Ag heterostructures, yielding an effective Bi spin Hall angle of approximately 1. By establishing a direct correlation between atomic-scale integrity and charge-to-spin conversion, this study provides design principles to improve the reliability of Bi-based SOT devices and offers a robust framework for interpreting spin–charge interconversion in Bi and Bi/Ag systems.

We demonstrate experimentally how the nucleation of skyrmions in an $\mathrm{Ir}, \mathrm{Co}$, and $\mathrm{Pt}$ based magnetic multilayer is affected by introducing a layer dependent sign for the Dzyaloshinskii-Moriya interaction (DMI). In one stack, the bottom half of the stack is given a positive DMI and the top half a negative DMI, and as a result, the in-plane component of the dipolar field is aligned parallel to the effective field of the DMI in every layer, enhancing the effective DMI. We show that this enhanced DMI facilitates the nucleation and stability of skyrmions using both current-driven and laser-induced skyrmion nucleation. In the devices with an enhanced effective DMI, the density of nucleated skyrmions is greater by up to a factor $\sim 20$ and skyrmions can be observed in stronger magnetic fields—suggesting that their stability is also improved. These results show that skyrmion nucleation depends strongly on the magnitude of the effective DMI in a magnetic multilayer and that the dipolar field within such a multilayer presents an effective route towards controlling the effective DMI, and thereby, the nucleation of chiral magnetic textures.

Topological insulators and skyrmion-hosting, chiral magnetic multilayers are two well-explored areas of modern condensed matter physics, each offering unique advantages for spintronics applications. In this paper, we demonstrate the optimization process for the growth of a ${\mathrm{Bi}}_2{\mathrm{Se}}_3/\text{buffer}/{[\mathrm{Pt}/\mathrm{CoB}/\mathrm{Ru}]}_{\times N}$ heterostructure that combines these two material classes: the ${\mathrm{Bi}}_2{\mathrm{Se}}_3$ epilayer was grown by molecular beam epitaxy before transfer under ultrahigh vacuum to a separate growth chamber where the polycrystalline metallic multilayer was sputter deposited. The structure of the samples was characterized by cofitted x-ray and polarized neutron reflectometry measurements and scanning transmission electron microscopy. Polarized neutron models and standard magnetometry show that a buffer layer exceeding a critical thickness is required to obtain the desired uniform, perpendicular magnetic anisotropy in every magnetic layer in the multilayer. Samples with both Ta and Mo buffers were used requiring thicknesses of 1.5 and 0.9 nm, respectively. In minimizing the ${\mathrm{Bi}}_2{\mathrm{Se}}_3$ terracing, buffered samples yield well-defined, out-of-plane, magnetic domains suitable for spin-orbit torque-induced manipulation as determined by x-ray photoemission electron microscopy.

Transition metal oxides exhibit a wide range of tunable electronic properties arising from the complex interplay of charge, spin, and lattice degrees of freedom, governed by their $d$ orbital configurations, making them particularly interesting for oxide electronics and (electro)catalysis. Perovskite oxide heterointerfaces offer a promising route to engineer these orbital states. In this work, we tune the $\mathrm{Co}3d$ orbital occupancy in ${\mathrm{LaCoO}}_3$ from a partial $d^7$ to a partial $d^5$ state through interfacial engineering with ${\mathrm{LaTiO}}_3$, ${\mathrm{LaMnO}}_3$, ${\mathrm{LaAlO}}_3$, and ${\mathrm{LaNiO}}_3$. Using x-ray absorption spectroscopy combined with charge transfer multiplet calculations, we identify differences in the Co valence and spin state for the series of oxide heterostructures. ${\mathrm{LaTiO}}_3$ and ${\mathrm{LaMnO}}_3$ interfaces result in interfacial charge transfer towards ${\mathrm{LaCoO}}_3$, resulting in a partial $d^7$ orbital occupancy, while a ${\mathrm{LaNiO}}_3$ interface results in a partial Co $d^5$ occupancy. Strikingly, a ${\mathrm{LaAlO}}_3$ spacer layer between ${\mathrm{LaNiO}}_3$ and ${\mathrm{LaCoO}}_3$ results in a Co $d^6$ low-spin state. These results indicate that the Co spin state, like the valence state, is governed by the interfacial environment. High-resolution scanning transmission electron microscopy imaging reveals a clear connection between strain and spin configuration, emphasizing the importance of structural control at oxide interfaces. Overall, this work demonstrates that interfacial engineering simultaneously governs orbital occupancy and spin state in correlated oxides, advancing spin-engineering strategies in correlated oxides and offering new insights for the rational design of functional oxide heterostructures.

Three-dimensional printing of advanced functional materials via direct ink writing requires the design and processing of soft solids or yield stress materials with high solids concentrations. The deformation, flow, and microstructure evolution of such complex soft materials are central in additive manufacturing extrusion technologies. In this study, we investigate both bulk properties and microscopic dynamics using rheo-microscopy, particle tracking, and birefringence mapping. This work presents an integrated framework that maps bulk rheology to local spatiotemporal heterogeneities during yielding of soft materials by combining oscillatory rheology experiments with simultaneous in situ imaging. Using a Pluronic F127 hard gel matrix with increasing concentrations of silica fillers as a model for direct ink writing formulations, we quantify the evolution of deformation pathways under large-amplitude oscillatory shear tests with increasing concentration $\left(\mathrm{\Phi }\right)$. Mapping local events onto bulk rheological metrics unveils a consistent trend from a matrix-dominated to a filler-dominated deformation regime. At low concentrations $(\mathrm{\Phi }\lesssim 0.31)$, the matrix dominates the yielding mechanism, leading to an affine-banding-fracture pathway. However, at high concentrations $(\mathrm{\Phi }>0.31)$, the filler-dominated system undergoes multiple local events under small deformations, from which cracks propagate and fracture the material into yielded and solid like regions. This work reconciles bulk and local observations in a flow regime map for particle suspensions in a gel matrix, highlighting when a soft material exhibits the desired affine flow and when it undergoes catastrophic failure. The results demonstrate that the deformation of highly concentrated composites is complex, where heterogeneous yielding and fracture coexist and negatively impact printability and shape fidelity. The experimental evidence presented in this work provides a timely avenue toward understanding the heterogeneous deformation and flow of complex soft materials, which play a critical role in a wide breadth of applications beyond 3D printing.

Strain and domain engineering offer powerful routes to control phase and domain stability in ferroelectric thin films. While most studies have focused on (100)-oriented growth, the impact of lower-symmetry orientations remains underexplored. We address this knowledge gap with first-principles-based molecular dynamics simulations for the example of prototypical ferroelectric perovskites under (110) strain. Epitaxial (110) strains may indeed outperform the widely studied (100) orientation, as even modest strain values stabilize a diverse set of metastable nanoscale states with potential high functional tunability. In this regime, the films exhibit multidomain configurations with domain wall normals oriented along the clamped in-plane or the relaxed out-of-plane directions and heterophases in ${\mathrm{BaTiO}}_3$ and ${\mathrm{KNbO}}_3$. Besides, complex superdomain patterns and antiferroelectriclike domains are observed in ${\mathrm{PbTiO}}_3$. These metastable nanoscale configurations may allow for large reversible responses.

Shear bands lie at the root of fracture initiation in bulk metallic glasses and amorphous polymers. For silicate glasses, in contrast, studies have largely emphasized permanent volumetric strain, commonly referred to as densification. Here, we systematically investigate indentation-induced fracture in two distinct families of aluminoborosilicate glasses. The results demonstrate that plastic shear flow plays a decisive role in governing fracture initiation. In addition, molecular dynamics simulations reveal a pronounced composition dependence of softening associated with plastic shear flow, closely mirroring the experimentally observed propensity for strain localization. We conclude that silicate glasses conform to a universal pattern of rupture initiation governed by the localization of shear-deformation, aligning with a broad range of amorphous materials, including bulk metallic glasses and glassy polymers.

High-entropy alloys provide an ideal platform for investigating superconductivity in the presence of extreme chemical disorder, lattice distortion, and magnetic impurity effects. Herein, we report a systematic study of the structural, normal-state, and superconducting-state properties of ${\left(\text{TiVTa}\right)}_{0.6}{\text{Nb}}_{0.4-x}{\text{Cr}}_x$ high-entropy alloys with $x=0$, 0.05, and 0.20. All compositions crystallize in a single-phase body-centered-cubic structure, with space group Im-$3m$. Our detailed analysis includes magnetization, resistivity, and specific-heat capacity measurements. The superconducting transition temperature is progressively suppressed from 4.68 to 2.59 K and the upper critical field is decreased from 5.77 to 3.87 T with increasing Cr content in the structure. Heat capacity measurements confirm $s$-wave weak-coupling superconductivity with a superconducting gap within the BCS limit in all the materials. The suppression of transition temperature follows Abrikosov-Gor'kov behavior, identifying magnetic impurity scattering from Cr as the dominant pair breaking mechanism. First-principles calculation reveals severe local lattice distortion characterized by a large atomic size mismatch $\delta =5.5\%$ and a substantial average atomic displacement $(\mathrm{\Delta }d=0.22\AA )$. The interatomic distance distribution exhibits broadened coordination shells with partially filled gaps between nearest-neighbor shells, reflecting strong deviations from ideal lattice positions while retaining long-range crystalline order.

We report comprehensive thermodynamic and neutron scattering measurements on the $S=3/2$ antiferromagnet ${\mathrm{Cs}}_2{\mathrm{CoI}}_4$, a member of the thoroughly studied family of frustrated magnets ${\mathrm{Cs}}_{2}M{X}_4$ ($M=\mathrm{Cu}$, Co, Ru, $X=\mathrm{Br}$, Cl, I, O). Unlike previously studied members, ${\mathrm{Cs}}_2{\mathrm{CoI}}_4$ undergoes a structural phase transition, for which we determine the low-temperature crystallographic structure. The resulting symmetry reduction strongly affects both the magnetic exchange interactions and single-ion anisotropy. Despite the large parameter space, we propose a minimal magnetic Hamiltonian that reasonably captures the observed excitation spectrum, analyzed using extended SU(4) linear spin-wave theory.

Chemical substitution in crystalline quantum materials is a powerful way to explore the consequences of strong spin-orbit coupling on their structural and electronic properties. In this work, we present an investigation of thin films of the $\mathrm{La}{Pn}_2(Pn=\mathrm{Sb},\mathrm{Bi})$ class of layered square-net intermetallics. We report the growth of ${\mathrm{LaBi}}_2$ with a pristine layer-by-layer growth mode, classifying it as a good metal displaying superconductivity at $\sim 0.55\text{K}$. Compared to ${\mathrm{LaSb}}_2$, we attribute the enhanced metallic behavior and improved growth dynamics of ${\mathrm{LaBi}}_2$ to significant relativistic corrections to its electronic band structure and the resulting impact on both surface energy and intrinsic phonon scattering.

Thermal transport in complex solids is governed by local structure, defects, and anisotropy, yet most continuum models still rely on oversimplified and homogenized conductivities. Here, we bridge atomistic and continuum descriptions by building finite element (FE) models directly from the site-projected thermal conductivity (SPTC), an atomic-level decomposition of the Green–Kubo thermal conductivity. We introduce a toolkit, the “Simulator Collection for Atomic-to-Continuum Scales (SCACS)”, which uses a graph neural network to predict SPTC on large atomic structures, coarse-grains these fields into anisotropic conductivity tensors, and embeds them into the heat-flow FE equation with a customized, anisotropy-aware adaptive mesh refinement scheme. Applied to silicon nanostructures, the resulting FE models act as representative volume elements, reproduce bulk conductivities, and capture interfacial and defect-driven anisotropy while maintaining thermodynamic consistency. Additionally, SCACS predicts experimental conductance trends and fields. This work demonstrates a general route for transferring atomistic transport information into device-scale thermal simulations with physics-based approximations.