Nanoglasses (NGs) consist of amorphous grains joined by glass-glass interfaces (GGIs), yet the atomic-scale mechanisms by which these interfaces control plasticity remain unsettled. Here, we combine molecular dynamics of ${\mathrm{Cu}}_{64}{\mathrm{Zr}}_{36}$ with the activation-relaxation technique to explicitly sample thermally activated events and map the potential-energy landscape of NGs with distinct interfacial geometries. We find that Cu surface segregation in the precursors persists as a diffuse enrichment at the consolidated interfaces, creating regions of local compositional and structural heterogeneity. Spatially resolved activation-energy distributions reveal that these GGIs host a persistent population of low-barrier excitations largely absent from the bulklike cores. While external strain amplifies the low-energy tail of the distribution, the onset of plasticity is dictated by the intrinsic energetic softness of the interfaces. Macroscopically, this preexisting population of soft sites suppresses abrupt shear localization, leading to a curtailed linear regime and distributed deformation. We further show that variations in mechanical response between architectures are governed by the interfacial volume fraction, while the fundamental deformation mechanism remains invariant. These results quantitatively link interfacial structure to the potential-energy landscape, establishing GGIs as preferred nucleation sites for shear transformations and providing a physics-based foundation for tailoring the mechanical response of amorphous alloys.

${\mathrm{Ba}}_4{\mathrm{SbRu}}_3{\mathrm{O}}_{12}$ crystallizes with a structure that consists of clusters of three face-sharing Ru-centered octahedra $\left({\mathrm{Ru}}_3{\mathrm{O}}_{12}\right)$ connected via Sb-centered octahedra. Rietveld refinements of both x-ray and neutron powder diffraction data confirm the absence of Sb/Ru antisite mixing. Variable temperature neutron diffraction measurements reveal a phase transition on cooling below 100 K from the aristotype structure with $R\overline{3}m$ symmetry to a monoclinic structure with $\mathrm{C}2/m$ symmetry. The phase transition is driven by displacements of $\mathrm{B}{\mathrm{a}}^{2+}$ cations and, as such, only subtly perturbs the geometry of the ${\mathrm{Ru}}_3{\mathrm{O}}_{12}$ clusters. The Ru $4d$ orbitals overlap to form delocalized molecular orbitals that span the trioctahedral cluster. At high temperature (T ≥ 200 K), the cluster adopts an $S=3/2$ intermediate spin state, but upon cooling to low temperature, susceptibility data suggest a gradual transition to an $S=1/2$ low spin state. The presence of $\mathrm{S}{\mathrm{b}}^{5+}$ ions with a [Kr] $4d^{10}$ electron configuration minimizes interlayer superexchange interactions between clusters, thereby maintaining the frustration of the 2D triangular network. ${\mathrm{Ba}}_4{\mathrm{SbRu}}_3{\mathrm{O}}_{12}$ shows no signs of magnetic ordering down to 0.3 K, yet Curie-Weiss fitting of high-temperature susceptibility suggests strong antiferromagnetic interactions $({\theta }_{\mathrm{CW}}=-378 \mathrm{K})$. The low-temperature specific heat evolves linearly with temperature, suggestive of a gapless quantum spin liquid. The combination of small magnetic quantum number, minimal chemical disorder, geometric frustration, and lack of long-range magnetic order makes ${\mathrm{Ba}}_4{\mathrm{SbRu}}_3{\mathrm{O}}_{12}$ an intriguing quantum spin liquid candidate that merits further study.

Magnetic compensation in rare-earth iron garnets (REIGs) offers a unique setting in which competing sublattice moments can give rise to non-collinear (canted) magnetic configurations, where the sublattice magnetizations are not aligned with each other or with the external magnetic field. We show that this compensation regime can possibly also host nontrivial magnetic textures. To explore this behavior, we investigated (111)-oriented epitaxial ${\mathrm{Tb}}_3{\mathrm{Fe}}_5{\mathrm{O}}_{12}$/Pt heterostructures across the compensation temperature region using combined transverse magneto-transport and polar Kerr microscopy. Notably, we observe a topological Hall–like signal in the vicinity of the compensation temperature, a feature often interpreted as evidence for skyrmions in the absence of direct imaging. Here, in contrast, complementary Kerr microscopy reveals instead a non-collinear multidomain state which collapses outside the compensation regime, correlating directly with the appearance and disappearance of the spin Hall topological Hall effect (SH-THE) signal. These observations cannot be accounted for by a simple multi-anomalous-Hall-effect model, ruling out common artifacts as the origin, but indicate a topologically nontrivial contribution to the Hall response. These results establish strained REIG films as a tunable platform for exploring topological responses arising from compensation-driven non-collinear ferrimagnetic phases.

Ternary semiconductors with chalcopyrite structure are of growing interest for electronic, energy-conversion, and spintronic applications. Using angle-resolved photoemission spectroscopy, we directly map the band structure of ${\mathrm{CdGeAs}}_2$, the prototypical chalcopyrite described by a modified Kane model that predicts the coexistence of flat bands and highly dispersive linear states. The combined effect of tetragonal distortion and broken inversion symmetry reduces the band degeneracy, allowing us to resolve three distinct states at the top of the valence band, with band velocities comparable to those reported in Dirac semimetals. We further probe the spin-to-charge conversion properties of ${\mathrm{CdGeAs}}_2$ by optically injecting spin-polarized carriers and detecting the resulting inverse spin Hall effect (ISHE). The photon-energy dependence of the ISHE signal and theoretical calculations of the optically injected spin polarization allow us to identify the specific valence-to-conduction transitions responsible for net spin accumulation and to estimate the spin diffusion length. These results demonstrate that chalcopyrite semiconductors provide a versatile platform for optospintronics.

The recent experimental observation of thermal rectification in a graphite Tesla valve suggests a phonon hydrodynamic mechanism beyond linear regime whose physical origin remains yet elusive. Here we uncover the correlation between nonreciprocal heat transfer and nonlinear phonon hydrodynamics by directly solving the nonlinear phonon Boltzmann transport equation with first-principles input. Pronounced thermal rectification and an unexpected crossover are unveiled in a prototypical asymmetric graphite ribbon. We reveal two underlying nonlinear effects including large phonon drift velocity and temperature-dependent phonon scattering rates which are dominant in hydrodynamic and diffusive regimes, respectively. Furthermore, the crossover behavior in graphite is shown to be governed by the competition between collective phonon drift and phonon excitation. This work thus establishes a theoretical framework for nonreciprocal phonon heat transport in nonlinear hydrodynamic regime and offers guidance for future theoretical and experimental studies on thermal functional devices based on collective phonon flow.

Improving the spin mixing conductance at the ferromagnet/heavy metal (FM/HM) interface with a low Gilbert damping constant in the FM layer is a key requirement for developing efficient spintronic devices. To evaluate the potential of ${\mathrm{Co}}_2\mathrm{Fe}{\mathrm{Ga}}_{0.5}{\mathrm{Ge}}_{0.5}$ as the FM layers in such structures, epitaxial ${\mathrm{Co}}_2\mathrm{Fe}{\mathrm{Ga}}_{0.5}{\mathrm{Ge}}_{0.5}$ single-layer and ${\mathrm{Co}}_2\mathrm{Fe}{\mathrm{Ga}}_{0.5}{\mathrm{Ge}}_{0.5}/\mathrm{Pt}$ bilayer films were deposited on MgO substrates using magnetron sputtering, and their Gilbert damping constants were evaluated from ferromagnetic resonance spectra. While the single-layer samples exhibit a low damping constant of $\sim 1.07\times {10}^{-3}$, an enhancement in the damping constant was observed in the bilayer samples due to spin pumping across the ${\mathrm{Co}}_2\mathrm{Fe}{\mathrm{Ga}}_{0.5}{\mathrm{Ge}}_{0.5}/\mathrm{Pt}$ interface, from which relatively large spin mixing conductance ($g_{\mathrm{eff}}^{\uparrow \downarrow }$) of $\left(2.78\pm 0.09\right)\times {10}^{19}{\mathrm{m}}^{-2}$ was evaluated. Further, to investigate the effect of interface property on $g_{\mathrm{eff}}^{\uparrow \downarrow }$, ultrathin ($\sim 0.2$ nm) Cu, Ni, Ru, Ta, or Cr insertion layers were introduced between the ${\mathrm{Co}}_2\mathrm{Fe}{\mathrm{Ga}}_{0.5}{\mathrm{Ge}}_{0.5}$ and Pt. Inserting a nonmagnetic (NM) Cu layer results in a pronounced decrease of $g_{\text{eff}}^{\uparrow \downarrow }$, whereas the FM Ni layer leaves $g_{\text{eff}}^{\uparrow \downarrow }$ nearly unchanged. In the case of Ru and Ta insertion layers, a modest reduction in $g_{\text{eff}}^{\uparrow \downarrow }$ is observed despite their NM nature. The antiferromagnetic Cr insertion layer also causes a small decrease in $g_{\text{eff}}^{\uparrow \downarrow }$. The observed change in $g_{\mathrm{eff}}^{\uparrow \downarrow }$ depends on the insertion material, indicating that their physical properties, such as magnetic, nonmagnetic, antiferromagnetic, light or heavy metal, reflect on $g_{\mathrm{eff}}^{\uparrow \downarrow }$.

In this work, we develop a rapid reactive vapor transport technique to efficiently utilize limited isotopically pure precursors, particularly gaseous ${}^{18}\mathrm{O}_2$, and synthesize mm-scale, high-quality isotope-enriched crystals within few-minute growth durations. We unlock this capability by using metallic molybdenum precursors with high source temperatures ($900{}^{\circ }\mathrm{C}$) and total pressures ($\sim 1$ atm) to maximize precursor efficiency and yield. Subsequently, we grow $\alpha \text{−}\mathrm{Mo}{\mathrm{O}}_3$ single crystals with high and uniform enrichment levels of ${}^{98}\mathrm{Mo}$ and ${}^{18}\mathrm{O}$ isotopes in several different permutations. As probed by Raman spectroscopy, modest and significant phonon energy redshifts occur following ${}^{98}\mathrm{Mo}$ and ${}^{18}\mathrm{O}$ enrichment, respectively. By demonstrating control over both molybdenum and oxygen isotopic enrichments, we establish a powerful tool to advance nanophotonics and thermal management goals using $\alpha \text{−}\mathrm{Mo}{\mathrm{O}}_3$. This work is motivated by the possibility to enhance and engineer lattice vibrational mode phenomena including thermal conduction and hyperbolic phonon polariton dispersion—with particular interest in comparing the effects of light and heavy element enrichment.

The type-II Weyl semimetal ${\mathrm{WTe}}_2$ is a key material for exploring emergent quantum phenomena; therefore, there is intense demand for high-quality single crystals. Here, we report the successful growth of ultra-high-quality ${\mathrm{WTe}}_2$ single crystals using an improved Te flux method, achieving a world-record residual resistivity ratio (RRR) reaching $\sim 4000$, nearly doubling the previous record. These crystals exhibit an extremely large magnetoresistance of $\sim 1.3\times {10}^7\%$ and an average carrier mobility of $4.1\times {10}^5\mathrm{c}{\mathrm{m}}^2{\mathrm{V}}^{-1}{\mathrm{s}}^{-1}$ at 2 K and 9 T, both surpassing previous records. By systematically comparing crystals spanning a wide range of RRR values, we demonstrate that crystal quality strongly influences low-temperature quantum transport and Fermi surface (FS) properties in ${\mathrm{WTe}}_2$. The exceptional quality and size of our crystals enabled magnetic torque measurements and the first observation of de Haas-van Alphen (dHvA) quantum oscillations in ${\mathrm{WTe}}_2$. Furthermore, combining Shubnikov-de Haas and dHvA oscillations allows for a reliable three-dimensional mapping of the FS below 9 T. Through an angular-dependent analysis using both probes, we determine the complete set of FS parameters over the full angular range. The nearly constant and very small Dingle temperature $(1\sim 2 \mathrm{K})$ indicates long quantum lifetimes and weak, nearly isotropic scattering, highlighting the intrinsic electronic character of the ultra-high-quality ${\mathrm{WTe}}_2$ crystals. Our work demonstrates the critical role of crystal quality in unveiling the intrinsic electronic states of quantum materials and provides a general strategy for improving the quality of other telluride crystals, enabling further advances in quantum materials research.

A machine-learned interatomic potential (MLIP) for multilayer $\mathrm{Mo}{\mathrm{S}}_2$ was developed using the ultrafast force field (UF3) framework. The UF3 MLIP reproduces key properties in strong agreement with DFT including lattice constants, interlayer binding energies, and phase stability. Furthermore, the potential reasonably captures the phonon spectra and the highly anisotropic elastic tensor across monolayer (1H) and bulk (2H, 3R) $\mathrm{Mo}{\mathrm{S}}_2$ phases. Critically, defect and edge formation energies are captured with high fidelity, exhibiting a strong correlation with DFT (R² = 0.91) across ten defective monolayers and reproducing the difference between the free energies of zigzag and armchair edges within 5% of DFT. Nonequilibrium molecular-dynamics simulations reveal layered homoepitaxial growth consistent with experimental observations, demonstrating the formation of van der Waals gaps between successive epilayers and triangular domains bounded by zigzag edges. The robust UF3 MLIP, which is only approximately two times slower than the fastest empirical potentials, enables large-scale atomistic simulations of $\mathrm{Mo}{\mathrm{S}}_2$ epitaxial growth.

Hydrogen is an element frequently found within the lattice of the ${\mathrm{CuInSe}}_2$ (CIS) chalcopyrite and its alloys in solar-cell devices, in many occasions introduced intentionally to passivate the electrical activity of existing defect centers. The present study reports first-principles calculations of the formation energies of the intrinsic defects of the CIS compound and their interaction with hydrogen. This interaction was also studied by analyzing muon-spin spectroscopy observations that probed the evolution of the spin relaxation of this lighter hydrogenic isotope. The calculations covered an extended range of growth conditions and regions of the CIS phase diagram, through the elemental chemical potentials, leading to $p$-type and $n$-type material. From the final results, the most plausible trapping centers for monatomic hydrogen were identified through a self-consistent solution of the electroneutrality equation as a function of the growth conditions. The copper vacancies were found to be the defects with the higher concentration for $p$-type and $n$-type CIS, with the exception of copper-rich and maximally indium-poor conditions, where the Cu-to-In antisite strongly competes as the dominant acceptorlike defect. Defect association of hydrogen with both of these acceptor defects led to trapping with full and partial passivation, respectively, and binding energies of $\approx 0.6$ eV for the resulting defect complexes. The calculated energy landscape of the hydrogen interaction with the copper vacancy contains two energy minima, which control the local diffusion pathways and trapping energy of hydrogen at this defect. Calculations based on the nudged elastic-band method and transition-state theory led to the local trapping and detrapping energy barriers and associated dissociation temperature. The analysis of the muon-spin data showed clear evidence of muon trapping at native defects in the CIS lattice with the copper vacancy providing the best match of the calculated muon-spin relaxation with the experimental value.

In their 2023 article [Phys. Rev. Mater. 7, 075401 (2023)], Adhikari et al. predicted “excellent phase stability against decomposition” for all 12 ${\mathrm{Cs}}_{2}M\mathrm{Sb}{X}_6$ ($M=\mathrm{Cu}$, Ag, Na, K, Rb, Cs; $X=\mathrm{Cl}$, Br) halide double perovskites (HDPs). However, this optimistic claim relied on decomposition pathways limited to binary products, neglecting critical ternary competing phases. By rigorously incorporating all possible decomposition routes with experimentally validated structures, we demonstrate that only ${\mathrm{Cs}}_2{\mathrm{AgSbCl}}_6$ ($\mathrm{\Delta }{H}_{\mathrm{d}}=3.9$ meV/atom) and ${\mathrm{Cs}}_2{\mathrm{NaSbCl}}_6$ ($\mathrm{\Delta }{H}_{\mathrm{d}}=1.8$ meV/atom) are thermodynamically stable, while the remaining 10 HDPs are either marginally metastable (for ${\mathrm{Cs}}_2{\mathrm{AgSbBr}}_6, \mathrm{\Delta }{H}_{\mathrm{d}}=-2.6$ meV/atom) or intrinsically unstable. Notably, Cu(I)-based systems—such as ${\mathrm{Cs}}_2{\mathrm{CuSbCl}}_6$ and ${\mathrm{Cs}}_2{\mathrm{CuSbBr}}_6$ ($\mathrm{\Delta }{H}_{\mathrm{d}}=-37.6$ and −40.1 meV/atom)—exhibit severe instability due to Cu(I)'s inherent aversion to octahedral coordination, a key destabilizing mechanism previously overlooked. These results reconcile computational predictions with experimental synthesis feasibility, resolving long-standing discrepancies. This Comment underscores the necessity of modeling realistic competing phases and comprehensive decomposition thermodynamics in stability assessments of emerging multicomponent materials, challenging oversimplified approaches in materials design.

We respond to the Comment by Xiao et al. on our work [Phys. Rev. Mater. 7, 075401 (2023)], which questions the thermodynamic stability analysis of ${\mathrm{Cs}}_{2}M\text{Sb}X{}_6$ halide double perovskites. The Comment argues that the stability assessment is affected by the choice of decomposition pathways and by the structural models used for $\text{Cs}X$ compounds. Here we clarify that our original work evaluated thermodynamic stability through decomposition enthalpies with respect to experimentally motivated competing phases rather than formation energies relative to elemental references. We further discuss the role of alternative decomposition pathways, metastability, and experimental synthesis conditions in determining the realizability of halide double perovskites. We show that while the additional pathways considered in the Comment provide useful complementary insight, they do not invalidate the thermodynamic framework or the principal conclusions of our original study.

The search for novel nitride superconductors with superior mechanical properties is highly demanded for many potential applications, which, however, have been scarcely succeeded for the late $5d$ transition-metal nitrides, especially for the binary W-N compounds. Here we report the experimental identification of superconductivity in cubic $\mathit{cP}6\text{-WN}$ with the NbO-type structure by electrical transport, magnetization, and specific heat measurements, based on high-pressure synthesized samples. The superconducting properties of $\mathit{cP}6\text{-WN}$ are well determined and it belongs to a bulk type-II superconductor with a critical onset temperature of $T_{\mathrm{c}}=2.86\mathrm{K}$, showing weak electron-phonon coupling, short coherence length, and high upper critical field, likely due to its unique electronic and structural features. Pressure may slightly enhance electron-phonon interactions for gently promoting its $T_{\mathrm{c}}$ up to 3.83 K at 81 GPa, indicating the remarkable robustness of its superconductivity to external stress. This, combined with its exceptional mechanical hardness that rivals that of tungsten carbide (WC), makes it a compelling candidate for fabrication of durable superconducting electronics and coatings operating under high-stress conditions.

The development of advanced photonic devices requires precise control of the optical properties of semiconductors. Gallium phosphide (GaP) is a promising wide-band-gap semiconductor of fascinating nonlinear optical applications. Here, we present experimental evidence for the success in fine-tuning the optical band gap of GaP single crystals by irradiation with MeV–GeV heavy ions of a wide range of ion fluences. The large variety of ion parameters from different ion-beam facilities made it possible to distinguish between the effects caused by nuclear energy loss and electronic energy loss, demonstrating the ability of avoiding possible unwanted structural damage. The presented results are essential for the application of ion-beam technology in the fabrication of nanophotonic devices by providing unique active materials, exhibiting the potential of emitting light with various controlled wavelengths of high precision. Furthermore, our findings are of high necessity for monitoring and establishing precautions for radiation effects at aviation altitudes and in space systems.

Avalanchelike plastic bursts in crystalline materials follow power-law statistics, but the scaling exponents and cutoff parameters vary widely in the literature ($\alpha$ ranging from 1 to 2.2), hindering predictive modeling. Since distributions do not follow Gaussian behavior, the average of plastic kinetics is not correctly defined. Larger-scale models that rely on average behavior are therefore fundamentally flawed. We performed extensive three-dimensional dislocation dynamics simulations of fcc Cu deformation across three orders of magnitude in dislocation density ($\rho =5\times {10}^{10}\text{to}2\times {10}^{12}{\text{m}}^{-2}$) under constant strain rates. Our results demonstrate that the power-law exponent ($\alpha \approx 1.6\pm 0.1$) is invariant to both dislocation density and loading direction, resolving previous inconsistencies. However, dislocation density strongly controls the power-law truncation scaling ($\mathrm{\Delta }{\gamma }_{\max }\propto b/\sqrt{\rho }$) and the distribution of avalanche-triggering stresses. We quantify correlations between slip system activities and show how individual system contributions evolve with avalanche size. These findings reconcile experimental scatter in avalanche statistics and provide quantitative scaling laws for mesoscale-to-continuum plasticity models.

Local atomic and electronic structures of the ${\mathrm{YbB}}_{12}$(001) surfaces are studied by scanning tunneling microscopy and spectroscopy at low temperatures for revealing the hybridized surface electronic states. The surface was prepared by annealing in an ultrahigh vacuum at $1200{}^{\circ }\mathrm{C}$ for one hour. The annealing process preferentially removed the surface Yb atoms, and the surface exhibits a homogeneous $c(2\times 2$) structure. On the inhomogeneous surface prepared by $1400{}^{\circ }\mathrm{C}$ annealing for several seconds, there are three types of local $c(2\times 2$) structures. The local tunneling spectra at 5 K near the Fermi energy on the surfaces exhibit characteristic features consisting of a co-tunneling lineshape due to the Kondo lattice formation and an additional central peak. On the homogeneous surface, the shape of the central peak depends on the tip-surface distance, suggesting the $f-d$ hybridized nature of the surface electronic states.

The metallic oxide ${\mathrm{RuO}}_2$ hosts a fascinating edge case of magnetism: while nonmagnetic in ideal bulk material, density functional theory (DFT) predicts an altermagnetic ground state within the $\mathrm{DFT}+U$ method. The magnetic state of strained or doped thin films remains controversial, but evidence for a nontrivial magnetic state is ample. Here, I study the altermagnetic ground state of ${\mathrm{RuO}}_2$ on a higher rung of Jacob's ladder of density functional approximations, the meta-GGA level including the kinetic energy density and the density Laplacian. While the workhorse functional of solid-state physics is a generalized gradient approximation (GGA), the modern ${\mathrm{r}}^2\text{SCAN-L}$ functional has been established as a general-purpose functional which can replace GGA, while systematically improving solid-state properties without introducing spurious errors like erroneous magnetic ground states. Comparison of local spin-density approximation $\left(\mathrm{LSDA}\right)+U, \mathrm{GGA}+U$, and meta-$\mathrm{GGA}+U$ results on ${\mathrm{RuO}}_2$ shows systematic enhancement of the exchange interaction, leading to a reduction of the onset value of the Hubbard $U$ parameter at different levels of density functional approximation. However, the magnetic ground state, studied at the experimental lattice constants, remains nonmagnetic with ${\mathrm{r}}^2\text{SCAN-L}$. I demonstrate that altermagnetism is easily formed upon lattice expansion, hole doping, and uniaxial strain on the $c$ axis. The ${\mathrm{r}}^2\text{SCAN-L}$ calculations set conservative thresholds for distortions and doping levels for the onset of altermagnetism in a parameter-free framework.