Two-dimensional type-II topological semimetals (TSMs), characterized by strongly tilted Dirac cones, have attracted intense interest for their unconventional electronic properties and exotic transport behaviors. However, rational design remains challenging due to the sensitivity of band tilting to lattice geometry, atomic coordination, and symmetry constraints. Here, we present a bottom-up approach to engineer ideal type-II nodal line semimetals (NLSMs) in van der Waals bilayers via atomic intercalation. Using monolayer $h$-AlN as a prototype, we show that fluorine-intercalated bilayer AlN (F@BL-AlN) hosts a symmetry-protected type-II nodal loop around the $E_F$, enabled by preserved mirror symmetry $\left({\mathcal{M}}_z\right)$ and tailored interlayer hybridization. First-principles calculations reveal that fluorine not only tunes interlayer coupling but also aligns the Fermi energy with the nodal line, stabilizing the type-II NLSM phase. The system exhibits tunable electronic properties under external electric and strain fields and features a Van Hove singularity that induces spontaneous magnetism, undergoing a transition from a type-IV antiferromagnetic metal to a ferromagnetic topological semimetal with increasing strain. This work provides a versatile platform for designing type-II NLSMs and offers practical guidance for their experimental realization.

The orbital Hall effect has emerged as a fundamental phenomenon in the burgeoning field of orbitronics, offering a robust paradigm for the generation and manipulation of orbital angular momentum. Particularly, two-dimensional valleytronic materials have emerged as highly promising platforms for investigating this effect. Concurrently, Floquet engineering via periodic optical driving provides a powerful nonequilibrium pathway to dynamically control topological quantum states. In this work, we employ Floquet theory to investigate the band topology and the corresponding evolution of orbital transport in a gapped graphenelike model driven by circularly polarized light, aiming to dynamically tune both the magnitude and sign of the orbital angular momentum. We reveal that the interplay between the optical field and intrinsic spin-orbit coupling (SOC) fundamentally reshapes the topological phase transitions. Specifically, SOC functions as a spin-valley-dependent mass correction that breaks the synchronization of photoinduced band inversions. This desynchronization drives the system into a unique mixed topological phase, where only a single spin band within a specific valley undergoes band inversion. Consequently, the orbital transport exhibits a pronounced spin-valley coupled character: within the same valley, the Berry curvature and orbital magnetic moment for the two spin channels acquire opposite signs, leading to highly tunable, valley-resolved orbital angular momentum transport. By further evaluating the orbital Hall angle, we demonstrate that a giant orbital Hall angle emerges in the vicinity of the insulating gap due to the suppression of longitudinal charge transport. Compared with bulk transition metals, this gap-engineered feature provides a more favorable platform for the study and manipulation of orbital angular momentum transport.

We develop a microscopic theory of magnon-exciton drag effect in a bilayer van der Waals antiferromagnetic semiconductor CrSBr. Effective exciton-magnon coupling arises from an orbital mechanism: Magnons tilt the layer magnetizations, enabling charge carrier tunneling that mixes intralayer and interlayer excitons and thereby modulates the exciton energy. We derive the effective Hamiltonian of exciton-magnon coupling, based on our calculation of the magnon spectrum taking into account short-range exchange interaction between Cr-ion spins, single-ion anisotropy, and long-range dipole-dipole interactions. We show that despite rather small renormalization of exciton's energy and effective mass by the exciton-magnon interaction, the three key two-magnon processes, exciton-magnon scattering, two-magnon absorption by an exciton, and two-magnon emission, are highly efficient. By solving the Boltzmann kinetic equation, we evaluate a short exciton-magnon scattering time which is in the sub-ps range and strongly decreases with the increase in magnon population. Hence, exciton-magnon scattering is likely to be dominant over other scattering processes related to exciton-phonon and exciton-disorder interactions. We demonstrate that nonequilibrium magnons can efficiently drag excitons, resulting in a large and nearly isotropic exciton propagation that can significantly exceed the intrinsic anisotropic diffusion. Our results provide a theoretical basis for recent observations of anomalous exciton transport in CrSBr [F. Dirnberger et al., Nat. Nanotechnol. 21, 65 (2026)] and establish magnon-exciton drag as a powerful mechanism for controlling exciton propagation in magnetic systems.

Alternative theories of quantum statistics provide an avenue for exploring novel physics beyond bosons and fermions, yet experimental verification of their existence in nature proves a challenging task. Among these theories, it has recently been suggested that $R$ parastatistics can be realized as quasiparticle excitations in many-body systems. In this paper, we build on this idea by showing that signatures of $R$ parastatistics can be observed as flavor-charge separation in one-dimensional (1D) systems. We consider a generalized version of the Luttinger model (LM) and show that bosonization persists when the $R$ paraparticles have fermi-surface-like structures. These $R$ parafermions can satisfy generalized exclusion principles beyond conventional Pauli's. We show that density waves of all $R$ parafermions can always be bosonized, but flavor waves act like bosons only for a certain subclass of $R$ parafermions. We derive the conditions for bosonization by analyzing the LM spectrum, showing that bosonization applies only to low-temperature systems. Signatures of flavor-charge separation then become apparent as distinct dispersion profiles when we turn on interparticle interactions. This points to potential observations of flavor-charge separation in 1D systems that host emergent $R$ paraparticles.

We demonstrate an alternative approach based on a complex-valued inverse temperature and partition function to probe quantum phases of matter with nontrivial spectra and dynamics. It leverages thermofield dynamics (TFD) to quantitatively characterize quantum and thermal fluctuations, and exploit the correspondence between low-energy excitations and Fisher zeros. Using the quantum XY chain in an external field as a test bed, we show that the oscillatory gap behavior manifests as oscillations in the long-time dynamics of the TFD spectral form factor. We also identify giant bubbles, i.e., large-scale closed lines, of Fisher zeros near the gapless XX limit. They provide a characteristic energy scale that seems to contradict the predictions of the low-energy theory of a featureless Luttinger liquid. We identify this energy scale and relate the motion of these giant bubbles with varying external field to the transfer of spectral weight from high to low energies. The deep connection between Fisher zeros, dynamics, and excitations opens up promising avenues for understanding the unconventional gap behaviors in strongly correlated many-body systems.

The geometry of a physical system is intimately related to its spectral properties, a concept colloquially referred to as “hearing the shape of a drum.” Three-dimensional topological insulator nanowires in a strong magnetic field $B$ generally host Dirac-type quantum Hall (QH) surface states. The surface itself is shaped by spatial variations of the wires' cross section, yielding a curved geometrical background, the “drum,” with imprints in the corresponding QH spectra. We show that the latter are composed of two different classes. The first one is asymptotically insensitive to the surface shape, scaling as $B^{1/2}$, like regular planar QH states. Instead, the second has an asymptotic $B$-field dependence intimately related to the wire geometry. We further demonstrate that an (axial-symmetric) curved nanowire surface possesses a reciprocal partner surface, such that the respective QH spectra are dual to each other upon exchanging angular momentum and magnetic flux. Notably, a cone-shaped nanowire, and the Corbino geometry as its limiting case, has a reciprocal partner with a dual QH spectrum that is $B$-field independent, with corresponding nonmagnetic QH-type states. We support our analytical findings by numerical results for $B$-field ranges and wire geometries within reach of current experiment.

As emerging ferroelectric (FE) materials, ultrathin two-dimensional (2D) sliding FEs without a phase-matching bottleneck usually exhibit pronounced second-harmonic generation (SHG) responses. Despite that the structural polarity of sliding FEs can be precisely detected via SHG characterizations, distinguishing the orientations of sliding ferroelectricity based on SHG responses has rarely been realized, as SHG intensities for upward and downward polarization states are supposed to be same. In the current work, combining computational simulations and experimental characterizations, the orientation of sliding ferroelectricity is demonstrated to be readily distinguishable via SHG responses in 2D ${\mathrm{SnP}}_2{\mathrm{S}}_6$ (${\mathrm{SnP}}_2{\mathrm{Se}}_6$), a potential sliding FE material. Specifically, owing to the unique symmetry operation within FE-${\mathrm{SnP}}_2{\mathrm{S}}_6$ (${\mathrm{SnP}}_2{\mathrm{Se}}_6$), the intersection between ${\chi }_{xxx}$ and ${\chi }_{yyy}$ SHG susceptibility coefficients with opposite signs leads to the effective rotation of SHG polar directions upon switching of sliding ferroelectricity. Moreover, the remarkable dependence of SHG polar directions on the orientation of sliding ferroelectricity is further validated by experimental characterizations performed on ${\mathrm{SnP}}_2{\mathrm{S}}_6$ crystal in a single FE domain structural form. In this work, we open an avenue for in situ detecting of the ferroelectricity orientation of 2D sliding FEs based on SHG nonlinear optical responses and demonstrate the controllable optical nonlinearity for slidetronics applications.

The equation of state (EOS) of hydrogen isotopes under extreme conditions is fundamental to planetary science and inertial confinement fusion (ICF), yet experimental constraints across broad thermodynamic regimes remain sparse. We report laser-driven shock measurements on hydrogen and deuterium statically precompressed to record pressures of 5.1 and 6.2 GPa, respectively. By coupling an integrated static-dynamic compression platform with a rigorous precompression-corrected impedance-matching framework, we extract high-precision pressure-density-temperature data up to 158.8 GPa for ${\mathrm{H}}_2$ and 281.9 GPa for ${\mathrm{D}}_2$. These measurements systematically expand the accessible phase space, exhibiting excellent agreement with a wide-range EOS model and establishing stringent benchmarks for modeling giant planetary interiors and ICF plasmas.

The description of electron-electron scattering presents challenges in the microscopic modeling of the interaction of ultrashort intense laser pulses with solids. We extend the semiclassical approach based on the Vlasov equation [M. Tani et al., Phys. Rev. B 104, 075157 (2021)] to account for dynamic electron-electron scattering by introducing the Vlasov-Uehling-Uhlenbeck (VUU) equation. We further couple the VUU equation with Maxwell's equations to describe the laser pulse propagation. We apply the present approach to simulate laser-electron interactions in bulk and thin-film aluminum, focusing on energy absorption and transport. Our calculation results reveal that electron-electron scattering affects energy absorption more significantly under $p$ polarization than under $s$ polarization, highlighting the role of the nonuniform surface potential. Our simulations also show that the energy transport extends beyond the optical penetration depth, which is consistent with observations in previous laser ablation experiments. The developed Maxwell-VUU approach is expected to advance the understanding of intense laser-material interactions not only as a cost-effective alternative to the time-dependent density functional theory (TDDFT), but also by incorporating fermionic two-body collisions whose description is limited in TDDFT.

We study prethermal time quasicrystalline (TQC) order in a quasiperiodically driven chain of noninteracting spin-1/2 particles. The drive consists of two parts, switched on and off periodically with frequency ${\omega }_d$: (i) disordered Ising interactions, with exchange couplings chosen from a symmetric interval $[-J/2,J/2]$, allowing random antiferromagnetic or ferromagnetic nearest-neighbor couplings, together with a random transverse field; and (ii) a rotating transverse magnetic field with frequency $\mathrm{\Omega }$. The ratio $\mathrm{\Omega }/{\omega }_d$ is chosen to be irrational, producing multiple incommensurate frequencies and yielding quasiperiodic dynamics beyond Floquet theory. Using exact diagonalization, we analyze the time autocorrelation function, dynamical structure factor, and entanglement entropy (EE). In the high-frequency regime, robust spectral peaks at incommensurate frequencies (not integer multiples of the fundamental drives) signal quasiperiodic time-translation symmetry breaking (QTTSB). The EE exhibits sublinear power-law growth followed by a prethermal plateau, indicating suppressed resonant heating due to an energy scale mismatch. The nonequilibrium lifetime increases rapidly with driving frequency. Unlike symmetric disorder sampling, an asymmetric distribution of the Ising exchange couplings induces collective spin rigidity, enhancing the system's resistance to heating. The TQC phase remains stable against next-nearest-neighbor (NNN) exchange perturbations and rotational imperfections, with robustness comparable to discrete time crystals (TCs) under periodic driving. Our results establish this quasiperiodically driven system as a platform for long-lived nonequilibrium temporal order, revealing the interplay of disorder, collective rigidity, and quasiperiodic driving.

A dynamical bulk-edge relation in quantum walks has been theoretically proposed and experimentally observed, in which a power-law dependence of the bulk loss probability is associated with a pronounced peak of loss probability at the edge. This behavior has been proven to arise from imaginary gap closing and the non-Hermitian skin effect in the infinite limit without boundary effects. However, in a finite-size chain, we find that boundary scattering can suppress this edge burst. Meanwhile, imaginary gap opening, together with the non-Hermitian skin effect, can also induce a large loss probability at the edge. Our results provide insights into finite-size quantum dynamics.

We present a comparative Raman scattering study of metallic rutile oxides ($\mathrm{Ru}{\mathrm{O}}_2$ and $\mathrm{Ir}{\mathrm{O}}_2$) and insulating rutiles ($\mathrm{Ti}{\mathrm{O}}_2$ and $\mathrm{Sn}{\mathrm{O}}_2$). Temperature-dependent Raman spectra reveal that metallic compounds exhibit pronounced phonon frequency hardening $[\omega \left(11K\right)-\omega \left(300K\right)=\mathrm{\Delta }\omega \approx 6-10\mathrm{c}{\mathrm{m}}^{-1}]$, whereas the insulating rutiles show only modest hardening $\mathrm{\Delta }\omega \approx 1-3\mathrm{c}{\mathrm{m}}^{-1}$. In contrast, the linewidth changes $\mathrm{\Delta }\mathrm{\Gamma }\approx 1–7\mathrm{c}{\mathrm{m}}^{-1}$ do not display a systematic metallic-insulating classification. Fits with the conventional Klemens anharmonic decay model reproduce the overall temperature trends but yield inconsistent anharmonic parameters for the metallic compounds when benchmarked against insulating rutile analogs. A modified Klemens framework, incorporating an additional $T^2$ correction to the phonon frequency arising from the electronic contribution to the phonon self-energy, quantitatively accounts for the enhanced renormalization observed in metallic systems. These results establish finite nonadiabatic electron-phonon coupling in metallic rutiles and demonstrate that phonon renormalization can be identified even in the absence of observable Fano asymmetry in the phonon line shapes.

Motivated by the objective of quantifying the energetic cost of accessing boundary phases through local control, we investigate here a simple, analytically tractable quantum impurity model. This model exhibits a rich boundary phase diagram, characterized by phases with different numbers of edge states. By considering a local quench protocol that drives the system out of equilibrium, we calculate exactly the resulting quantum work distribution across these phases. Our results show that the presence of edge states strongly alters this distribution. In particular, we analytically determine the signatures of these states in the low-, intermediate-, and high-energy sectors.

The development of two-dimensional (2D) magnetic materials provides an ideal platform for the discovery and manipulation of topological spin textures. However, most 2D materials can only support one kind of spin textures, which severely limits their diversity and potential applications. In this study, we investigate the $\mathrm{CrZn}{X}_2$ ($X=\mathrm{S}/\mathrm{Se}/\mathrm{Te}$) monolayers with ${\mathrm{D}}_{2\mathrm{d}}$ symmetry using first-principles calculations, atomistic spin simulations, and micromagnetic simulations. Our results demonstrate that domain-wall antiskyrmions can be stably hosted in $\mathrm{CrZnS}{\mathrm{e}}_2$, and under biaxial strain, they can transform to antiskyrmions. Furthermore, by tuning the in-plane magnetic field, we can induce a topological phase transition from antiskyrmions to antibimerons. We then investigate the dynamics of antiskyrmions and reveal the dependence between the antiskyrmion Hall angle and the angle of spin current injection. Under spin-orbit torque (SOT) driving, the speed of the antiskyrmion can be effectively controlled by adjusting the direction of the spin current. This design allows the antiskyrmion to move precisely along the track direction by applying an oblique spin current, thereby preventing its annihilation at the edges. This study not only uncovers diverse topological spin structures in $\mathrm{CrZnS}{\mathrm{e}}_2$ but also proposes a practical method for current-driven manipulation of antiskyrmions.

We present a comprehensive study of the low-temperature magnetism and field-tuned thermodynamics of the layered Shastry-Sutherland compound ${\mathrm{Eu}}_2{\mathrm{MgSi}}_2{\mathrm{O}}_7$. ${\mathrm{Eu}}^{2+}$ ions ($4f^7, S=7/2$) form a quasi-two-dimensional orthogonal-dimer network, realizing a large-spin Heisenberg system on a Shastry-Sutherland geometry that is prone to geometric frustration. Magnetic susceptibility and magnetization measurements reveal nearly isotropic ${\mathrm{Eu}}^{2+}$ moments with weak antiferromagnetic interactions. Specific-heat data uncover a primary long-range ordered state at $T_{\mathrm{N}1}=0.8\mathrm{K}$ and a second anomaly near $T_{\mathrm{N}2}=1.0\mathrm{K}$ that is rapidly suppressed by magnetic field, suggesting that it is more field sensitive and may not correspond to an independent thermodynamic phase transition. By separating the magnetic heat capacity, we determine the full magnetic-entropy surface $S_{\mathrm{m}}(T,B)$, which captures the smooth field-driven evolution from the ordered state to a correlated and eventually polarized paramagnetic regime. The resulting isentropic trajectories demonstrate efficient adiabatic demagnetization, allowing cooling from 1.5–3.1 K at 5 T to minimum temperatures of 0.21–0.50 K. Comparison with the benchmark refrigerant ${\mathrm{Gd}}_3{\mathrm{Ga}}_5{\mathrm{O}}_{12}$ shows that ${\mathrm{Eu}}_2{\mathrm{MgSi}}_2{\mathrm{O}}_7$ exhibits enhanced sub-Kelvin magnetic heat-storage capacity, reflecting its large accessible spin entropy and weak interactions. These results establish ${\mathrm{Eu}}_2{\mathrm{MgSi}}_2{\mathrm{O}}_7$ as a rare example of a Eu-based frustrated magnet that combines weak interactions, a well-resolved low-temperature ordered state, and tunable thermodynamics suitable for sub-Kelvin cryogenic applications.

Chemical substitution offers an effective route to tune magnetic ordering and magnetocaloric performance in rare-earth (RE) oxides for cryogenic refrigeration. Here, we investigate the structural evolution, magnetic properties, and magnetocaloric effect of polycrystalline zircon-type ${\mathrm{Gd}}_{1-x}{\mathrm{Er}}_x{\mathrm{VO}}_4$ $(x=0, 0.1, 0.25, 0.5, \text{and} 0.75)$. Powder x-ray diffraction confirms that all samples crystallize into the tetragonal zircon structure without detectable impurity phases. Substitution of ${\mathrm{Gd}}^{3+}$ by the smaller ${\mathrm{Er}}^{3+}$ ion produces a systematic lattice contraction and modifies the magnetic behavior of the RE sublattice. The magnetic ordering temperature is suppressed from 3.65(2) K in ${\mathrm{GdVO}}_4$ to 2.76(2) K in ${\mathrm{Gd}}_{0.9}{\mathrm{Er}}_{0.1}{\mathrm{VO}}_4$, accompanied by a weakening of the spin-flop-like field-induced anomaly observed in the parent compound. A low Er concentration correspondingly improves the low-temperature magnetocaloric performance, with ${\mathrm{Gd}}_{0.9}{\mathrm{Er}}_{0.1}{\mathrm{VO}}_4$ exhibiting a maximum magnetic entropy change of 45.1 $\mathrm{J}{\mathrm{kg}}^{-1}{\mathrm{K}}^{-1}$ for ${\mu }_0\mathrm{\Delta }H=7\mathrm{T}$. These results demonstrate that weak Er substitution effectively tunes the competition among exchange interactions, dipolar coupling, and magnetic anisotropy, optimizing the balance between magnetic ordering and available spin entropy in zircon-type RE vanadates, which is crucial for developing efficient cryogenic refrigeration materials.

We present an in-depth analysis of the orbital magnetism by means of the so-called modern theory based on the Berry phase across distinct classes of materials-$d$ transition-metals, $sp$ metals, and transition metal dichalcogenides—highlighting the importance of the microscopic nature of band structure characteristics on the orbital magnetization. We adopt a gauge-covariant formulation of the modern theory proposed in Lopez et al. [Phys. Rev. B 85, 014435 (2012)], which enables the calculation of orbital magnetism in a controlled manner in any chosen gauge of Wannier functions and gives the total contribution as a gauge-invariant measurable. This captures consistently the contributions due to the anomalous position, velocity, and orbital angular momentum of a Wannier basis, as well as the contributions due to Hamiltonians such that their sum is gauge-invariant. For $d$ transition metals, we find that the atom-centered approximation captures the majority of the total contribution given by modern theory, which we attribute to the localized nature of $d$ electrons. However, $5d$ metals tend to exhibit relatively larger deviation between the two methods than $3d$ metals do, as $5d$ electrons are more delocalized than $3d$ electrons. On the other hand, $sp$ metals exhibit a strong deviation between the two methods, where the large kinetic energy of $sp$ electrons is important. Finally, in $1\mathrm{H}\text{−}{\mathrm{MoS}}_2$, we find that the valley orbital moment at each valley far exceeds the atomic limit orbital moment of $d$ electrons due to coherent hybridization between valence and conduction bands in direct band gaps. Our work elucidates the interplay of the chemical nature of electronic orbitals and the effect of band structures in a consistent manner and highlights the role of the Berry phase in orbital magnetism. The results suggest a promising direction of orbitronics beyond controlling atomic orbitals, in which the orbital magnetism can be greatly enhanced by exploiting the Berry phase.

We examine how an anomalous Josephson current influences odd-frequency superconducting correlations in two Josephson junction geometries. The first consists of two ferromagnetic layers between conventional $s$-wave superconductors, with magnetizations along the $x$ and $y$ axes, forming a bilayer junction. The second contains three ferromagnetic layers between two $s$-wave superconductors, with magnetizations along the $x, y$, and $z$ axes, forming a trilayer junction. Both systems are analyzed in the short- and long-junction limits. In the bilayer case, where no anomalous Josephson current is present, odd-frequency equal-spin triplet correlations develop pronounced peaks at finite magnetizations in the short-junction limit for both tunneling and transparent ferromagnetic interfaces. The odd-frequency mixed-spin triplet correlations also exhibit peaks at finite magnetizations for tunneling ferromagnetic interfaces, whereas for transparent ferromagnetic interfaces they display both peaks and zeros. In the trilayer case, where an anomalous Josephson current exists, similar peaks in both equal- and mixed-spin odd-frequency triplet correlations occur at finite magnetizations for tunneling and transparent ferromagnetic interfaces. The spatial profiles of these correlations remain largely unaffected by the anomalous Josephson current. The Josephson diode efficiency is finite and reaches its maximum at magnetizations corresponding to the peaks of the anomalous Josephson current. Overall, our results show that the anomalous Josephson current has only a marginal influence on odd-frequency spin-triplet pairing. This indicates that the emergence of odd-frequency correlations and the Josephson diode effect are largely independent phenomena, contrary to earlier conjectures. Analysis of the long-junction limit leads to the same qualitative conclusions for both configurations.

Vortex motion plays a central role in determining the resistance of two-dimensional superconductors, both in the context of the Berezinskii-Kosterlitz-Thouless (BKT) transition and in the mixed state of type-II superconductors under magnetic fields. In this study, we introduce an anisotropic pinning potential to investigate vortex-induced resistance across the BKT transition and the upper critical field $H_{c2}$ transition. Our results demonstrate that the anisotropic pinning potential gives rise to distinct critical temperatures and upper critical fields along two orthogonal directions of current transport. These findings provide a general route toward the realization of multiple “critical temperatures” in two-dimensional superconductors.