Magnetic anisotropy is a pivotal parameter that determines the magnetic ordering behavior and plays an important role in practical applications of magnetic materials. However, its influence on thermodynamic properties remains experimentally unexplored. As an air-stable, antiferromagnetic (AFM) van der Waals (vdW) semiconductor, CrSBr exhibits unique uniaxial in-plane magnetic anisotropy, making it an ideal platform to elucidate these unresolved relationships. Herein, high-quality CrSBr single crystals are synthesized via a modified two-step chemical vapor transport (CVT) method. A comprehensive analysis using modified Arrott plots, the Kouvel-Fisher method, the Widom scaling law, and critical isotherm analysis confirms a possible direct crossover from the tricritical mean-field behavior to the 3D Ising behavior, suggesting non-negligible interlayer coupling in bulk CrSBr. Supported by first-principles calculations and molecular field approximations, a pronounced triaxial magnetic anisotropy is quantified, with relative anisotropy energy satisfying $K\left(b\to c\right)>K\left(b\to a\right)$. Notably, strong anisotropy energy overcomes the interlayer exchange coupling $\left(K>J{S}^2\right)$, driving a field-induced first-order spin-flip transition along the easy $b$ axis. The maximum magnetic entropy change ($-\mathrm{\Delta }{S}_{\mathrm{M}}^{\max }$) is 5.21, 5.09 and 4.74 J/(kg K) for $H\parallel b$, $H\parallel a$, and $H\parallel c$, respectively. Pronounced in-plane uniaxial magnetic anisotropy guarantees an anisotropic magnetocaloric effect, as evidenced by a negative linear correlation between $K$ and rotating magnetic entropy change $-\mathrm{\Delta }{S}_{\mathrm{M}}^{\mathrm{R}}$. These findings contribute to understanding of magnetism and associated thermodynamic properties in triaxially magnetically anisotropic CrSBr, thereby facilitating the tuning of magnetic anisotropy and exotic spin states in two-dimensional magnets.

Recent THz spectroscopy of the quantum paraelectric ${\mathrm{SrTiO}}_3$ (K. S. Kumar et al., arXiv:2501.15771) and a high-$T_c$ cuprate (D. Chaudhuri et al., arXiv:2503.15646) has renewed interest in energy relaxation in correlated electron systems. We consider a situation in which single-phonon scattering is forbidden by symmetry or momentum conservation, while two-phonon scattering is allowed. Solving the Boltzmann equation, we show that above the Bloch–Grüneisen temperature the energy relaxation rate from two soft transverse optical phonons exceeds the single-phonon one: while the latter scales as $1/T$, the former is linear in $T$. This dominance of two-phonon scattering invalidates the usual picture of energy diffusion arising from frequent scattering by subthermal phonons; instead, energy relaxes via rare scattering events involving thermal phonons. Below the Bloch–Grüneisen temperature, the energy relaxation rate scales as the single-particle rate, namely as $T^3$ for soft phonons. For anisotropic electron bands, an intermediate regime appears between two Bloch–Grüneisen temperatures, in which both allowed single-phonon and two-phonon processes scale as $T^2$.

We formally classify density functionals that utilize the full density Hessian as Hessian-level meta-generalized gradient approximations (HL-MGGAs), distinguishing them from standard meta-GGAs that rely on the orbital-dependent kinetic energy density or the density Laplacian. Within this broader class, we introduce a simplified, nonempirical functional, $\vartheta \text{−}\mathrm{PBE}$, and detail the general self-consistent implementation of HL-MGGAs within the projector-augmented-wave (PAW) method. By utilizing the complete set of spatial second-order density derivatives, the functional's underlying descriptor successfully distinguishes between distinct one-electron density limits, such as single-center atomic densities and two-center bonds, that standard iso-orbital indicators often conflate. Benchmarks across molecular and solid-state datasets reveal that while $\vartheta \text{−}\mathrm{PBE}$ delivers accurate chemisorption energies and molecular properties, challenges remain in predicting bulk lattice constants. Ultimately, this work demonstrates the physical utility and feasibility of designing orbital-independent, Hessian-based exchange-correlation functionals.

Slow twist-angle and heterostrain textures in twisted bilayer graphene provide a natural route to phase-space Berry geometry. We show that a purely geometric tetrad/shift sector does not generate mixed Berry curvature once the spin connection is treated consistently. By contrast, a projected textured mini-Dirac cone in twisted bilayer graphene acquires genuine mixed phase-space curvature. We analyze a controlled local Hall-bar limit with a one-dimensional texture and mirror $M_x$. In that limit, the pseudogauge gradient renormalizes only the longitudinal conductivity along the textured direction, while a dc nonlinear Hall response appears only when an additional valley-odd tilt generates a Berry-curvature dipole. Both geometric responses peak at the same local filling, ${\mu }_{\mathrm{loc}}=\sqrt{2}m$, providing a gate-tunable fingerprint of their common origin. All local-cone parameters and their texture susceptibilities are extracted from a heterostrained Bistritzer-MacDonald model at $\theta =1.3^{\circ }$. The tilt invoked in the transport estimates corresponds to heterostrain of only $0.03\%\text{–}0.2\%$, below values routinely imaged in devices. The resulting theory provides a local analytic framework for textured moiré Dirac materials and cleanly separates geometric, texture-induced, and transport-level ingredients relevant to realistic TBG.

We present a direct comparison of the optical gain in InGaAs quantum wells (QWs) and transition-metal dichalcogenide (TMD) monolayers (MLs), revealing a clear advantage of the latter in both material and modal gain. A central objective of this work is to quantify this gain advantage and to identify its microscopic origin using a state-of-the-art theoretical framework that combines first-principles electronic-structure calculations with many-body theory for the excited carriers. The superior gain performance of TMD MLs arises from their strongly enhanced interband Coulomb interaction. At the same time, the presence of nearby side valleys in the conduction band renders TMDs less favorable for maintaining excited carriers in optically active states. In contrast, the electronic band structure of InGaAs/GaAs QWs is inherently well suited for achieving population inversion. As a result, we find comparable transparency carrier densities in both systems, while the magnitude of the gain can be substantially larger in TMD MLs. Our analysis further shows that encapsulation of a ${\mathrm{WS}}_2$ ML in hBN mitigates the carrier drain into side valleys, thereby reducing the transparency carrier density compared with a ${\mathrm{WS}}_2$ ML on ${\mathrm{SiO}}_2$. A previously underexplored aspect is the Henry $\left(\alpha \right)$ factor, which governs the laser linewidth, chirp, and feedback tolerance. While InGaAs QWs exhibit unfavorably large $\alpha$ values near the transparency carrier density, ${\mathrm{WS}}_2$ encapsulated in hBN shows weakly negative values, indicating more favorable laser performance. Our results uncover a previously unrecognized potential of TMD MLs for laser applications and provide microscopically founded guidance for material choice, dielectric engineering, and device integration of ML-based gain media.

In this paper, we employ a modified Haldane lattice model to investigate the light-driven, spin- and valley-dependent anomalous Nernst effect in two-dimensional hexagonal topological systems. We demonstrate that two-dimensional buckled materials exhibit a hierarchy of electrically and optically tunable topological phases when subjected to off-resonant circularly polarized light in the presence of intrinsic spin–orbit coupling and a staggered sublattice potential. Within a Berry-curvature-driven transport framework, we systematically analyze charge-, spin-, and valley-resolved anomalous Nernst responses and identify their correspondence with distinct topological regimes. A finite charge Nernst conductivity arises under optical driving combined with spin–orbit coupling, whereas the generation of a pure valley Nernst current requires the simultaneous presence of sublattice asymmetry and off-resonant light. Substrate-induced inversion asymmetry further enables thermally driven valley currents with tunable magnitude and sign. We find that single-spin and single-valley Nernst responses occur in selected insulating and metallic phases, while the valley Nernst signal is suppressed in spin-polarized and anomalous quantum Hall phases. Extending our analysis to monolayer ${\mathrm{MoS}}_2$, we show that strong spin–orbit coupling and broken inversion symmetry allow fully spin- and valley-polarized Nernst currents over a broad energy window. The temperature dependence of the Nernst response exhibits characteristic signatures of topological phase transitions, establishing the anomalous Nernst effect as a sensitive probe of field-engineered band topology in two-dimensional Dirac materials.

In the article [Phys. Rev. B 77, 075119 (2008)], effective magnetic moments $p_{\mathrm{eff}}$ per Co site have been determined from magnetic susceptibility measurements for a series of ${\mathrm{Li}}_x{\mathrm{CoO}}_2$ samples. The nominal Li content $x$ (ranging theoretically from 1 to 0) determines the concentration of ${\mathrm{Co}}^{3+}$ ($x$) and ${\mathrm{Co}}^{4+}$ ($1-x$) that occupy the Co sites. Assuming that the ${\mathrm{Co}}^{3+}$ species is diamagnetic, the effective magnetic moment $p_{\mathrm{eff}}$ per ${\mathrm{Co}}^{4+}$ ion has been calculated from the experimentally determined effective magnetic moment $p_{\mathrm{eff}}$ per Co site and the nominal ${\mathrm{Co}}^{4+}$ concentration in the cited publication [Phys. Rev. B 77, 075119 (2008)] by assuming a purely linear relation between the effective magnetic moments and the concentrations. From the viewpoint of this comment's author, this linear approach is not valid and the linear effective magnetic moments $p_{\mathrm{eff}}$ utilized in the formulas in the cited article should be replaced by their squared values $p_{\mathrm{eff}}^2$. This comment provides the correct formulas for the calculations aimed to be performed in [Phys. Rev. B 77, 075119 (2008)] and recalculates the published values. Since for low ${\mathrm{Co}}^{4+}$ concentrations a high-spin species is discussed to exist in ${\mathrm{Li}}_x{\mathrm{CoO}}_2$ in numerous publications, correct handling of effective magnetic moments is of general interest in this discipline of research.

The Kitaev model is exactly solvable in terms of Majorana fermions hopping on a honeycomb lattice and coupled to a static ${\mathbb{Z}}_2$ gauge field, giving the possibility of $\pi$ vortices in hexagonal plaquettes. In the vortex-full sector and in the presence of a time-reversal–breaking three-spin term of strength $\kappa$, the energy spectrum is gapped, and the ground state possesses an even Chern number. An isolated vortex-free plaquette acts as a dual vortex and binds a fermionic mode at finite energy $\epsilon$ in the bulk gap. This mode is equivalent to two coupled Majorana zero modes located on the same dual vortex. In a continuum approximation, we analytically compute the Majorana wave functions and their coupling $\epsilon$ in the two limits of small or large $\kappa$. The analytical approach is confirmed by numerical perturbation theory directly on the lattice. The latter is in excellent agreement with the full numerics on a finite-size system. We contrast our results with states bound to an isolated vortex in a topological superconductor with even Chern number.

We analyze the impact of the lattice geometry on the thermodynamic transition to magnetically ordered phases in strongly interacting electron systems for various Bravais lattices in three, four, and five dimensions, including both local and nonlocal correlation effects. In a first step we use the dynamical mean-field theory (DMFT), which takes into account purely local correlations, to calculate the magnetic susceptibilities of the Hubbard model on three- (3d-sc), four- (4d-sc), and five- dimensional (5d-sc) simple cubic/hypercubic, as well as on three- dimensional body- (bcc) and face-centered (fcc) cubic lattices, and determine the transition temperature to the corresponding magneticallyordered state. In a second step, we exploit the dynamical vertex approximation $\left(\mathrm{D}\mathrm{\Gamma }\mathrm{A}\right)$, a diagrammatic extension of DMFT, to include the effect of nonlocal correlations which are particularly important in the vicinity of the corresponding phase transition. For the bipartite 3d-sc, 4d-sc, 5d-sc, and bcc lattices nonlocal fluctuations lead to a substantial reduction of the DMFT transition temperature consistent to the overall tendency of mean-field approaches to overestimate the stability of ordered phases. As expected, the magnitude of the difference between the DMFT, being exact in the limit of large connectivity/dimensions, and $\mathrm{D}\mathrm{\Gamma }\mathrm{A}$ transition temperatures decreases with increasing coordination number. On a more practical perspective, these results also provide a reasonable guidance to evaluate the expected overestimation of the DMFT ordering temperature for different material geometries. For the fcc lattice, on the other hand, the ordered phase observed in DMFT vanishes completely within $\mathrm{D}\mathrm{\Gamma }\mathrm{A}$ which is consistent with the existence of strong geometric frustration in this lattice.

Open quantum systems are often described by a Lindblad master equation, which relies on a set of approximations, most importantly the rotating-wave approximation, which is only valid for weak damping. In the Lindblad setting, dissipative processes are described through jump operators, distinguishing between absorption and emission of photons. This enables the simple identification of emitted photons, which provides a straightforward way to obtain the radiation statistics. Outside the rotating-wave limit, the Lindblad approach does not work. Open quantum systems can then be described by, e.g., the quantum Langevin equation. However, in this framework the number of emitted photons is not easily accessible. In this work, we point out how to obtain the photon counting statistics from a quantum Langevin equation and provide an expression for the photon current operator, for arbitrary systems coupled to linear environments. As an example, we employ the method to study the radiation statistics of a damped harmonic oscillator at finite temperature beyond the rotating-wave approximation. We show that even outside the rotating-wave limit, the most important contribution to the radiation statistics can be captured by an effective Lindblad equation, thus extending the range of possible applications of the Lindblad framework.

An empirical finding is that the ratio of glass transition temperature $T_g$ to the crystal melting temperature $T_m$ is near $\frac{2}{3}$ for many glass-forming materials. The key to understand the origin of the $\frac{2}{3}$ rule is the availability of a theoretical method to determine $T_m$ and its relation to $T_g$. In this paper, we compare the mean-square displacements of caged molecules in the glass $\langle u_a^2\left(T\right)\rangle$ with that in the crystal $\langle u_c^2\left(T\right)\rangle$, and surmise whether $\langle u_a^2\left(T\right)\rangle$ at $T_g$ and $\langle u_c^2\left(T\right)\rangle$ at $T_m$ have comparable values. If the surmise $\langle u_a^2\left(T_g\right)\rangle \approx \langle u_c^2\left(T_m\right)\rangle$ is realizable, it offers a method to determine $T_m$ and $T_g/T_m$. Justification of the surmise is made possible by the recent temperature-modulated differential scanning calorimetry experiments [M. Pyda et al., J. Phys. Chem. Lett. 17, 61 (2026)] in finding a reversible heat capacity signature in melting similar in shape and magnitude to that observed at glass transition in molecular and polymeric glass formers. Hence, present at $T_m$ is a structural relaxation involving the same molecules as that at $T_g$. The result motivated us to verify the surmise from neutron scattering data of four materials, ortho-terphenyl, cis-decalin, selenium, and glycerol, and by Brillouin light scattering data of ortho-terphenyl. Thus, the relation $\langle u_a^2\left(T_g\right)\rangle \approx \langle u_c^2\left(T_m\right)\rangle$ can be used as a criterion of melting. Our melting parameter ${\mathrm{\Delta }}_m$ ≡$\sqrt{\langle u_c^2\left(T_m\right)\rangle }/d_{\text{NN}}\approx \sqrt{\langle u_a^2\left(T_g\right)\rangle }/d_{\text{NN}}$ with $d_{\text{NN}}$ as the nearest-neighbor distance obtained for several materials varies over the range from 0.05 to 0.32. It seems that molecules of larger size and with stronger interaction have larger ${\mathrm{\Delta }}_m$ values.

Lanthanide ions exhibit characteristic emission originating from intra-$4f$ transitions. Among them, hypersensitive transitions (HSTs) are distinguished by their pronounced spectral tunability. Conventional HST emitters typically rely on dilute doping and host-to-$4f$ charge transfer, which are often limited by defect-induced quenching and transfer losses. Here, we observe a highly efficient HST channel independent of a host-to-$4f$ transfer in undoped, intrinsically luminescent europium-based double perovskites, and we identify the mechanisms that govern both the enhancement and loss of HST efficiency. In this system, a thermally activated doubly degenerate phonon mode of the $\mathrm{Eu}\text{−}{\mathrm{Cl}}_6$ octahedra relaxes the parity selection rule, thereby strengthening the HST emission. The HST oscillator strength is enhanced by a factor of 2–3 relative to that of the magnetic-dipole transition. Direct excitation into the ${}^{5}L_J$ level bypasses reverse energy transfer and yields a maximum quantum efficiency of nearly 70%. These findings provide insights into the design of efficient and spectrally tunable emission in lanthanide systems.

The anomalous Hall effect (AHE) is a hallmark transport phenomenon in ferromagnets arising from relativistic spin-orbit interaction. Here, we report an unexpected sign reversal of the AHE in $\mathrm{Ru}/{\left[\mathrm{Co}/\mathrm{Ni}\right]}_N$ multilayers controlled by the stacking sequence of the Ru layer. When Ru is placed beneath, rather than atop, the Co/Ni multilayers, the anomalous Hall signal switches from positive to negative. By systematically varying the multilayer repeat number $N$ and combining transport measurements with first-principles calculations, we show that this reversal originates from in-plane tensile strain imposed by the Ru underlayer, which reshapes the electronic structure and redistributes Berry curvature near the Fermi level. Our findings establish interfacial strain as an effective knob for tuning Berry-curvature-driven transport and suggest a pathway toward strain-controlled topological transport phenomena in magnetic multilayers.

Interlayer magnetic coupling in multilayered systems remains a central issue in the understanding and designing of functional low-dimensional magnetic heterostructures. In this work, we investigate the magnetic coupling between magnetostrictive layers with opposite magnetostriction constants that remains unaffected by the introduction of a nonmagnetic Cu spacer layer. We present in-plane hysteresis loops and ferromagnetic resonance spectra and show that angle-resolved ferromagnetic resonance experiments demonstrate a single resonance at all orientations. We, therefore, conclude that there is a magnetoelastically induced coupling between the two magnetic films despite the presence of a nonmagnetic Cu layer between them.

NbRe, a noncentrosymmetric superconductor with a transition temperature $T_{\mathrm{c}}$ of up to about 9 K, attracts interest for its strong antisymmetric spin-orbit coupling and suitability for single-photon detection. While bulk and thin-film polycrystalline NbRe are well studied, how superconductivity and vortex dynamics evolve with increasing grain size in thin films is largely unknown. Here, we investigate as-grown and annealed 20 nm-thick NbRe films, where annealing increases the average crystallite size from approximately 2 to 8 nm, and probe their resistance states via current-voltage $\left(I\text{−}V\right)$ measurements over a broad temperature and magnetic field range. In contrast to as-grown films, where the low-resistive state breaks down due to flux-flow instability, annealed films exhibit multiple voltage kinks in the $I\text{−}V$ curves. We attribute these kinks to the nucleation and growth of normal domains, as further suggested by time-dependent Ginzburg-Landau simulations. Overall, the annealed films form superconducting networks with vortex-channeling paths along the grain boundaries, while localized heating and voltage kinks may offer potential for discrete-resistance switching and sensing.

We introduce the non-Hermitian mosaic Maryland model, where a discrete modulation period and a non-Hermitian phase are incorporated into the potential, so that the Grempel-Longhi construction underlying the closed-form solution of the $\kappa =1$ Maryland model no longer applies for $\kappa \ge 2$. This model provides a unique platform to investigate how structural modulation governs localization in complex quasiperiodic potentials. Using Avila's global theory, we analytically derive the exact Lyapunov exponent and obtain explicit formulas for the complex mobility edges. Remarkably, for modulation periods $\kappa \ge 2$, the system intrinsically hosts $\kappa -1$ robust extended bands that persist independently of the potential strength and non-Hermiticity. We further characterize the topological nature of these phases via the spectral winding number. Unlike the standard Maryland model, the mosaic modulation induces mobility edges, and the resulting phase transitions are continuous. Numerical calculations of the inverse participation ratio (IPR) and fractal dimension (FD) confirm the analytical predictions for the asymptotic form of the mobility edges in the large non-Hermiticity limit. This work establishes structural design as a powerful degree of freedom for engineering wave transport and enhancing the robustness of extended states in non-Hermitian systems.

We present a combined theory-experiment study to quantify spin diffusion in the square lattice quantum spin-$1/2$ XY model at finite temperature. On the theory side, we leverage a recently developed dynamical high-temperature expansion method to faithfully capture the long spatiotemporal scales of the hydrodynamic regime. Experimental results are obtained from an optical lattice hard-core boson quantum simulator. The excellent agreement of spin diffusion constants marks a breakthrough in spin transport beyond one dimension and for the quantitative validation of state-of-the-art quantum simulation platforms. We also provide theory predictions for future experiments on dynamic spin conductivity or anisotropy-induced integrability breaking.

Unconventional superconductivity under strong Zeeman fields—particularly beyond the Pauli paramagnetic limit—remains a central challenge in condensed matter physics. The exotic Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, in particular, remains in need of definitive study within fundamental electronic models. Here we employ state-of-the-art finite-temperature and ground-state tensor network approaches to systematically explore the superconducting (SC) phase diagram of the $t\text{−}{t}^{\prime }\text{−}J$ model subjected to Zeeman fields. We find that zero-momentum $d$-wave superconductivity persists until the spin gap closes, coexisting with charge density waves. A novel $d$-wave FFLO phase emerges under a higher Zeeman field even above the Pauli limit, concomitant with a field-enhanced spin density waves. We identify these phases, characterized by the simultaneous presence of pairing condensate and density wave orders, as charge-2e supersolids. Analysis of Matsubara Green's function reveals that the FFLO pairing momentum is locked to the underlying Fermi surface. Our results provide microscopic insights into field-induced unconventional pairing mechanisms and reveal the long-sought FFLO state in a fundamental correlated electron model, offering a promising route for its realization in ultracold atom optical lattice.