Rydberg tweezer arrays provide a platform for realizing spin-1/2 Hamiltonians with long-range tunneling that decays as a power law with distance. We numerically investigate the effects of positional disorder and dimerization on the properties of excited states in such a one-dimensional system. Our model allows for continuous tuning of both the dimerization pattern and the disorder strength. Within the parameter space constrained by our geometry, we show that both mechanisms lead to a localized phase that does not resemble standard many-body localization. This phase can be understood as an ensemble of distinct Hilbert-space–fragmented realizations induced by small interspin separations. As dimerization is commonly associated with symmetry-protected topological (SPT) physics, we also examine the SPT states across the entire energy spectrum. Despite the presence of a partial spin-glass order, we argue that the system hosts an extensive fraction of SPT states.

The origin of the remarkable Curie temperature ($T_c$) enhancement in monolayer ${\mathrm{Fe}}_3{\mathrm{GaTe}}_2$ (FGaT, $T_c$ ∼ 240 K) relative to isostructural ${\mathrm{Fe}}_3{\mathrm{GeTe}}_2$ (FGeT, $T_c$ ∼ 130 K) remains unresolved. Here, we employ a combined energy mapping + spin spiral approach to disentangle competing intralayer and interlayer exchange interactions in ${\mathrm{Fe}}_{3}X{\mathrm{Te}}_2$ (FXT, $X=\mathrm{Ge}$,Ga). Our results reveal that FGaT's significant $T_c$ enhancement arises from a weakened intralayer antiferromagnetic coupling within the outer ${\mathrm{Fe}}_a$ layer concurrent with a strengthened interlayer ferromagnetic coupling between ${\mathrm{Fe}}_a$ and the middle ${\mathrm{Fe}}_b$ layer. Meanwhile, we quantitatively separate the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction from isotropic exchange mechanisms, revealing attenuation in both intralayer ${\mathrm{Fe}}_a\text{−}{\mathrm{Fe}}_a$ RKKY coupling and superexchange interactions. Furthermore, we identify strain as tuning knobs for improving the $T_c$ of the ${\mathrm{Fe}}_a$ sublattice, providing quantitative design principles for achieving room-temperature magnets. These findings resolve persistent questions on the origin of $T_c$ enhancement while establishing rational design strategies for novel two-dimensional magnetic materials.

Magnons are bosonic quasiparticles in magnetically ordered systems. Bosonic Bott index has been affirmed as a real-space topological invariant for a two-band ferromagnetic model. In this work, we theoretically investigate the topology and transport of magnons in a multiband bosonic kagome ferromagnetic model. We demonstrate the validity of the bosonic Bott indices of values larger than 1 in multiband magnonic systems by showing the agreement with Chern numbers in the clean limit and the bulk-boundary correspondence during the topological phase transition. For the high Bott index phase, the disorder-induced topological phase transition occurs in a multistep manner. Using a generalized Landauer-Büttiker formalism, we reveal how the magnon transport depends on Gilbert damping and disorder under coherent excitation or temperature difference. The results further justify the bosonic Bott index as a robust real-space topological invariant for multiband magnonic systems and provide insights into the transport of topological magnons.

Significant exchange bias (EB) is induced across the spin reorientation (Morin) transition (${\mathrm{T}}_{\mathrm{M}}$) in epitaxial $\alpha -{\mathrm{Fe}}_2{\mathrm{O}}_3\left(001\right)/{\mathrm{Ni}}_{81}{\mathrm{Fe}}_{19}$ (hematite/permalloy) heterostructures, far below the antiferromagnetic transition temperature. In contrast to typical exchange coupled systems, these heterostructures exhibit two distinct features: (i) exchange bias is established at the Morin transition, rather than the Néel ordering, and (ii) a qualitatively different temperature dependence where EB is confined to a narrow temperature window near ${\mathrm{T}}_{\mathrm{M}}$ instead of increasing monotonically upon cooling as in conventional systems. The temperature- and angular-dependent measurements imply that this thermal behavior is caused by separate transitions of the interfacial and bulk hematite spins. As a consequence, interdiffusion drastically alters the thermal dependence of EB, which highlights the role of the interfacial spins. Our study reveals that the spin reorientation transition breaks the magnetic isotropy at the antiferromagnetic hematite (001) surface and controls the interfacial exchange interactions. These results demonstrate that the spin reorientation transition in hematite, including its widely available doped variants, can be exploited to realize thermally programmable and temperature-selective exchange bias. With the growing interest in antiferromagnetic spintronics, they further show that spin reorientation transitions in antiferromagnets provide a tunable window independent of the Néel temperature for manipulating AFM spins and may assist Néel vector switching in spin torque devices.

Quantum many-body scars (QMBS) are exceptional eigenstates that defy thermalization, enabling long-lived coherent dynamics in strongly interacting systems. However, their stability under perturbations remains inadequately understood. In this work, we derive improved lower bounds on the thermalization time of QMBS under local perturbations with strength $\lambda$. Using both numerical simulations and analytical reasoning, we show that exact QMBS exhibit slow thermalization, with a timescale scaling as $\tau \sim \mathcal{O}\left({\lambda }^{-1/d}\right)$ owing to the stabilizing restricted spectrum-generating algebra (RSGA), which is a significant improvement over previous bounds [e.g., $\tau \sim \mathcal{O}\left({\lambda }^{-1/(d+1)}\right)]$. Counterintuitively, approximate QMBS can thermalize even more slowly under generic perturbations, exhibiting $\tau \sim \mathcal{O}\left({\lambda }^{-2}\right)$ scaling due to second-order perturbative effects in the absence of such protective structure. These distinct thermalization behaviors clarify how exact and approximate scars maintain coherence. Our work advances previous findings by establishing a tighter bound on the thermalization time, clarifying when scarred dynamics remain long-lived under weak but generic perturbations.

The sliding of van der Waals (vdW) bilayers can induce electric polarization in certain nonpolar two-dimensional (2D) materials. However, this mechanism does not apply to 2D materials with Bravais lattice symmetry (e.g., graphene), where the atomic structure and lattice symmetry have the same point group, preserving inversion symmetry across all stacking configurations. To overcome this limitation, multilayered vdW structures can be exploited for their diverse structural symmetries. In this work, we present a general theory for multilayer stacking ferroelectricity (MSF), which systematically analyzes whether and how different types of polarization can emerge in vdW multilayers composed of 2D materials with Bravais lattice symmetry. This theory clarifies the symmetry evolution during stacking and unifies previous work on sliding ferroelectrics, including tetralayer graphene. Guided by the MSF theory, we design a ferroelectric trilayer ${\mathrm{C}}_3\mathrm{N}$ that exhibits multidirectional in-plane polarization, inducing a strong bulk photovoltaic effect (BPVE) coupled with the ferroelectric order, which is absent in both monolayer and bilayer. These findings highlight the importance of the MSF theory in the design of 2D ferroelectrics for ferroelectric photovoltaic applications.

We theoretically investigate hole spins confined in a gate-defined quantum dot embedded in a GeSn/Ge/GeSn quantum-well structure. Due to the tensile strain in the Ge layer, the system effectively realizes a light-hole qubit. We systematically study how various morphological parameters influence the energy spectrum and the hyperfine coupling to the nuclear spin bath. The simulations are carried out using a realistic, fully atomic ${sp}^3{d}^5{s}^{*}$ tight-binding model. We also perform complementary density functional theory calculations of wave functions near the atomic cores and use them to parametrize the hyperfine‐interaction Hamiltonian. We evaluate the Overhauser field fluctuations and demonstrate that the strength of the hyperfine coupling for the lowest hole doublet crucially depends on the Sn content in the barrier. We highlight the conduction-valence band mixing, which leads to considerable $s$-type admixtures to the hole states, providing the dominant channel of hyperfine coupling due to the Fermi contact interaction.

Low-dimensional quantum fluids, where one can probe the effects of enhanced thermal and quantum fluctuations on macroscopic quantum wave functions, can be experimentally realized through transverse physical confinement of superfluid helium on scales smaller than the coherence length. Reaching this scale is difficult, requiring confinement in single or multiple pores with nanometer radii. Porous silicates such as MCM-41 have a pore radius larger than the coherence length of ${}^4\mathrm{He}$, and in this work we systematically explore the possibility of preplating pores with different elements to reduce the pore size without localizing the confined superfluid. Through a direct solution of the few-body Schrödinger equation combined with quantum Monte Carlo simulations, we explore the behavior of helium confined inside cylindrical nanopores for a range of preplating elements, including rare gases and alkali metals. For rare gases, we find that helium remains strongly attracted to the pore walls and any atoms in the core form an incompressible liquid. For alkali metals such as Cs, weak interactions between helium and the preplating material prevent localization near the walls and enable delocalization in the pore center. Our results extend previous results for helium wetting on flat two-dimensional coated substrates to the curved geometry inside nanopores, and demonstrate that alkali-metal preplated nanopores may enable a tunable one-dimensional confined quantum liquid of helium.

Self-sustained oscillators play a central role in the stabilization and synchronization of complex dynamical systems. A number of different physical systems are currently being investigated to clarify the importance of such active components in the quantum realm. Here we explore the properties of a driven-dissipative electron-photon hybrid system based on superconducting microwave resonators coupled resonantly to a voltage-biased double quantum dot (DQD). First, we establish a Hopf bifurcation at a critical value of the electron-photon coupling, beyond which an effective negative friction sustains steady limit-cycle oscillations of individual resonators. Second, we show that two such limit-cycle resonators coupled via the same voltage-biased DQD synchronize for small enough frequency detuning. A nonlinear photon Keldysh action is derived by perturbation theory in the effective circuit fine-structure constant, and the limit-cycle dynamics is analyzed in terms of resulting saddle-point and Fokker-Planck equations. In the Markovian limit of infinite bias voltage, these results are shown to agree well with the solution of a corresponding Lindblad master equation for the DQD resonator system.

In this work, combined with the optical spectroscopy and the first-principles calculations, we investigated the effect of lattice distortion on the band structure and magnetism of FeGe annealed at different temperatures. Our observations reveal that the sample annealed at $320{}^{\circ }\mathrm{C}$ experienced dramatic change in optical conductivity following the charge-density-wave (CDW) transition. Specifically, a substantial portion of the spectral weight (SW) in the low-energy region $(<0.4\mathrm{eV})$ was redistributed to the high-energy region $(0.8\sim 1.5\mathrm{eV})$, suggesting a reconstruction of the band structure. The sample annealed at $560{}^{\circ }\mathrm{C}$ did not exhibit a CDW transition, but it exhibited the same tendency of SW transfer from 300 to 5 K progressively. Through the first-principles calculations, we ascribed the band reconstruction to Ge1 atoms' dimerization along the $c$ axis and analyzed its affection to the magnetism. On the other hand, even though the CDW transition is absent in $560{}^{\circ }\mathrm{C}$ annealed sample, the high-temperature annealing induced lattice distortion, resulting in the same optical properties, further emphasized that the band reconstruction and the enhanced magnetism primarily come from the displacement of Ge1 atoms.

We investigate a hexagonal ${\mathrm{ScAl}}_3{\mathrm{C}}_3$-type antiferromagnet ${\mathrm{GdZn}}_3{\mathrm{P}}_3$ single crystal. Compared with antiferromagnetic topological material ${\mathrm{Eu}\mathit{M}}_2{X}_2$ $(M=\mathrm{Zn}, \mathrm{Cd}; X=\mathrm{P}, \mathrm{As})$, the ${\mathrm{GdZn}}_3{\mathrm{P}}_3$ features an additional ${\mathrm{ZnP}}_3$ trigonal planar units. Notably, single-crystal x-ray diffraction analysis reveals that Zn and P atoms within a trigonal planar layer exhibit significant anisotropic displacement parameters with space group $P{6}_3/mmc$. Meanwhile, a scanning transmission electron microscopy experiment demonstrates the presence of interstitial P atoms above and below the ZnP honeycomb lattice, suggesting potential ZnP bond instability within the ${\mathrm{ZnP}}_3$ trigonal layers. Concerning the triangular $\mathrm{G}{\mathrm{d}}^{3+}$ layer, the magnetic susceptibility χ(T) and heat capacity measurements reveal an A-type antiferromagnetic order at $T_N=4.5\mathrm{K}$. Below $T_N$, the in-plane χ(T) is nearly 4 times the χ(T) along $c$ axis, indicative of strong magnetic anisotropy for salt-flux-grown ${\mathrm{GdZn}}_3{\mathrm{P}}_3$ crystal. The density function theory calculation shows that ${\mathrm{GdZn}}_3{\mathrm{P}}_3$ is an indirect semiconductor with a band gap 0.27 eV, supported by the resistivity measurement on the polycrystal sample. Interestingly, Hall measurements of metallic ${\mathrm{GdZn}}_3{\mathrm{P}}_3$ crystals grown via salt flux reveal a low concentration of hole carriers, consistent with the previously mentioned presence of interstitial P atoms. Furthermore, these crystals exhibit a pronounced nonlinear anomalous Hall effect below $T_N$. In contrast, ${\mathrm{GdZn}}_3{\mathrm{P}}_3$ crystals grown by chemical vapor transport display weak semiconducting behavior. Despite exhibiting a similar $T_N$, the in-plane χ(T) below $T_N$ in the vapor-transport-grown crystal is approximately half in magnitude compared to that of the salt-flux-grown sample, which supports the hypothesis of charge carrier-mediated Ruderman-Kittel-Kasuya-Yosida interactions. These findings collectively establish ${\mathrm{GdZn}}_3{\mathrm{P}}_3$ as a compelling model system for investigating the coupling between charge carriers and triangular lattice magnetism within a two-dimensional framework.

We study magnetism in the electron-doped infinite-layer nickelate ${\mathrm{NdNiO}}_2$. We perform an unrestricted Hartree-Fock calculation for a tight-binding model which contains both nickel and neodymium orbitals. We reproduce the self-doping effect, which is the escape of charge onto the neodymium bands. By fixing all free parameters to realistic values we find that undoped ${\mathrm{NdNiO}}_2$ lies right outside the antiferromagnetic (AFM) region of the phase diagram. This is consistent with experiments, which find no long-range order in the ground state of ${\mathrm{NdNiO}}_2$, yet see short-range AFM correlations and broad magnetic excitations. We also find that the self-doping effect leads to a dramatic increase in the stability of the AFM solution upon electron doping—a behavior that is strikingly different from what is, for instance, observed in the cuprates. Finally, for smaller charge transfer energies than suggested for ${\mathrm{NdNiO}}_2$, the self-doping effect may be quite strong and stabilize various stripe configurations already on the mean-field level.

We investigate nonequilibrium electron dynamics in crystalline ZnO induced by ultrashort, relatively intense, infrared laser pulses. Our focus is on understanding the mechanism that facilitates efficient conduction band population in ZnO to enable optically pumped lasing. We consider two different pulse frequencies (in the near infrared and mid infrared) for which experimental data are available, and we calculate the electronic response of a ZnO crystal for a wide range of pulse intensities. We apply and compare three complementary theoretical approaches: the analytical Keldysh model, the numerical solution of the semiconductor Bloch equations, and real-time time-dependent density functional theory. We conclude that time-dependent density functional theory is a valid ab initio approach for predicting conduction band population, that offers an accurate enough description of static and transient optical properties of solids and provides physics insight into the intermediate excitation regime, where electronic excitations are determined by the interplay of intraband tunneling, a consequence of band bending, and interband multiphoton absorption.

Antichiral edge states, proposed as protected copropagating modes in the modified Haldane model, have since been studied in diverse systems. Through numerical calculation, we reveal that such antichiral edge states are unstable to disorder: they exhibit a shorter localization length than the bulk states. For specific disorders, the spatial bond current plot clearly depicts scattering, further demonstrating the fragility of such states. The results offer fresh perspectives on antichiral edge states in broader electronic and classical wave systems.

Understanding crystallization mechanisms at the atomic scale is critical for advancing glass-ceramics design and improving the predictive accuracy of classical nucleation theory (CNT). While CNT assumes sharp interfaces and isolated atomic jumps during crystal growth, emerging evidence suggests the presence of diffuse interfaces and cooperative atomic rearrangements. However, experimental characterization of interfacial regions remains challenging due to their nanoscale dimensions and dynamic nature. In this study, molecular dynamics (MD) simulations were employed to investigate the structural and dynamic evolution of the interface during the growth of lithium aluminosilicate (LAS) crystals, a widely used glass-ceramic system. Our findings reveal the existence of two distinct interfaces: (1) a pre-ordered structural interface with a temperature-dependent width, and (2) a diffusion interface characterized by gradients in atomic mobility. Contrary to CNT assumptions, crystal growth proceeds via cooperative rearrangements of network-forming atoms, with ring structures acting as key units of ordering. The width of the structural interface was found to increase with decreasing temperature, while the diffusion interface narrowed, highlighting the coupling between thermodynamic and kinetic factors during crystallization. These results refine existing crystallization theories by incorporating atomic-scale insights and provide a foundation for designing glass-ceramics with tailored properties.

We report our direct investigation on a built-in strain and its effect on magnetic properties in $\mathrm{Co}/{\mathrm{MoS}}_2$ heterostructure. With variation of Co thickness, tensile strain is built in monolayer ${\mathrm{MoS}}_2$ ranging from 0.7% to 1.9%. Magneto-optical Kerr microscopy reveals distinct changes in microscopic magnetic domain patterns with corresponding hysteresis loop modification by the strain from the ${\mathrm{MoS}}_2$ monolayer. Our work quantitatively demonstrates a correlation between magnetic properties and built-in strain, suggesting an interfacial built-in strain as an effective tool for controlling phonon and magnetic properties in a ferromagnet/two-dimensional bilayer system.

Valley polarization and altermagnetism are two emerging fundamental phenomena in condensed matter physics, offering unique opportunities for information encoding in novel energy-efficient devices. However, achieving electrical control over these properties in a single material remains a significant challenge. Here, we propose a general strategy to realize ferroelectric-valley (FE-valley) and FE-altermagnetic coupling in bilayer antiferromagnetic (AFM) honeycomb lattices based on an effective four-band spin-full $k·p$ model. Our proposal is validated in bilayer ${\mathrm{MnPTe}}_3$ through first-principles calculations. A spontaneous out-of-plane electric polarization occurs in AB- and BA-stacked configurations, reversibly switchable via interlayer sliding. Remarkably, polarization reversal simultaneously inverts both layer-resolved valley polarization and altermagnetic spin splitting. This dual control enables tunable layer-spin-locked anomalous valley Hall effects and an unprecedented magnetoelectric response in two-dimensional (2D) antiferromagnets. Our work provides a design principle for electrically programmable valleytronic and spintronic functionalities of 2D AFM materials, bridging fundamental symmetry-breaking mechanisms and practical device applications.

The effect of $c$-axis compression on the electronic structure and superconducting (SC) properties of the high-temperature SC cuprate ${\mathrm{La}}_{2-x}{\mathrm{Sr}}_x{\mathrm{CuO}}_4$ at different doping levels is investigated. The electronic structure of quasiparticle excitations is obtained within the effective five-band Hubbard model, using the equation of motion method for Green's functions based on Hubbard operators. The SC gap and $T_c$ are calculated by considering the exchange pairing mechanism, which involves not only the Zhang-Rice singlet but also excited two-hole triplet and singlet states. The energy of the $a_{1g}$ orbitals increases with increasing compression, and the $a_{1g}$ quasiparticle bands begin to strongly interact with the $b_{1g}$ bands at the top of the valence band. The reconstruction of the region of states that determine the SC properties results in a high density of states near the Fermi level. This mechanism leads to an increase in $T_c$ in the underdoped region with increasing compression. On the other hand, the renormalization of the pairing constants under compression results in a decrease in $T_c$. The competition between these two effects leads to the nonmonotonic behavior of $T_c$ under $c$-axis compression near optimal doping.