We uncover a nonlinear magnon transport mechanism in two-dimensional honeycomb antiferromagnets driven by pseudogauge fields induced by surface acoustic waves. Using semiclassical Boltzmann transport theory, we demonstrate that a first-order spin current emerges linearly with the strength of the Dzyaloshinskii-Moriya interaction, despite the magnon Berry curvature itself being Dzyaloshinskii-Moriya interaction independent, a result that reveals an unexpected dissipation-driven response. At second order, we show that the spin current is governed by the magnon Berry curvature dipole, establishing a direct analogy with the nonlinear anomalous Hall effect in electronic systems. Both contributions are found to be dissipative in nature, offering insight into symmetry-allowed spin transport beyond the linear response. Our findings identify a previously unexplored pathway for generating and controlling spin currents in antiferromagnets via dynamic strain fields, with potential implications for strain-engineered magnonic devices and low-power spintronics applications.

We present experimental results on electron transport in a bilayer electron system that consists of two uncoupled two-dimensional electron gases (2DEGs) formed in a double quantum well within a GaAs/AlGaAs heterostructure. Our measurements of the capacitance between the top gate and the 2DEGs as a function of varying magnetic fields at total integer filling factors reveal critical insights into the net interlayer charge transfer required for the layers to maintain equal electrochemical potentials. In instances where both layers operate in the quantum Hall effect regime, the magnetocapacitance demonstrates anticoercive hysteresis. In particular, the change in electron density linked to this hysteresis significantly surpasses that associated with equilibrium interlayer charge transfer, indicating that hysteresis and interlayer charge transfer arise from distinct phenomena. Furthermore, at high amplitudes of the alternating gate voltage, we observe a nonlinear change in magnetocapacitance, indicating a breakdown of the quantum Hall effect.

Spin-split antiferromagnets have significance for antiferromagnetic (AFM) spintronics due to their momentum-dependent spin polarization, which can be exploited for the control and detection of the AFM order parameter. Here, we explore the polar-layer stacking of AFM-ordered van der Waals bilayers driving the emergence of reversible electric polarization and nonrelativistic spin splitting (NRSS) of their band structure. Using the spin-space group approach and first-principles calculations, we explore $M\mathrm{P}{X}_3$ ($M=\mathrm{Mn}$ V; $X=\mathrm{S}$, Se) and 1T-${\mathrm{CrTe}}_2$ as representative two-dimensional AFM materials which exhibit different types of NRSS when stacked into a polar bilayer. We demonstrate that NRSS can have both altermagnetic and nonaltermagnetic origins and elucidate symmetry requirements for NRSS to be switchable by electric polarization. We argue that the electric polarization switching of NRSS in polar AFM bilayers may be more practical for device applications than the current-induced Néel vector switching.

We present the theory of the longitudinal spin Seebeck effect between a Heisenberg spin-$1/2$ chain and a conductor. The effect consists of the generation of a spin current across the spin chain-conductor interface in response to the temperature difference between the two systems. In this setup, the current is given by the convolution of the local spin susceptibilities of the spin chain and the conductor. We find the spin current to be fully controlled, both in the magnitude and the sign, by the backscattering interaction between spinons, fractionalized spin excitations of the Heisenberg chain. In particular, it vanishes when the spinons form a noninteracting spinon gas. Our analytical results for the local spin susceptibility at the open end of the spin chain are in excellent agreement with numerical density matrix renormalization group simulations.

Entanglement patterns reveal essential information on many-body states and provide a way to classify quantum phases of matter. However, experimental studies of many-body entanglement remain scarce due to their unscalable nature. The present Letter aims to mitigate this theoretical and experimental divide by introducing reduced fluctuations of observables, consisting of a sum of on-site operators, as a scalable experimental probe of the entanglement entropy. Specifically, we illustrate by density matrix renormalization group calculations in spin chains that the reduced fluctuations exhibit the same size scaling properties as the entanglement entropy. Generalizing previous observations restricted to special systems with conserved quantities, our work introduces an experimentally feasible protocol to extract entanglement scaling laws.

We propose that the quantum conditional mutual information (QCMI), computed with a suitably chosen partition of the system, serves as a powerful probe for detecting measurement-induced entanglement phase transitions in monitored quantum circuits. To demonstrate this, we investigate monitored variable-range Clifford circuits and identify the phase boundary between volume-law and area-law entanglement phases by performing finite-size scaling analyses of the QCMI. Assuming that the entanglement entropy exhibits a logarithmic dependence on system size at criticality in short-range interacting cases, we further show that the QCMI allows for the simultaneous determination of both the critical point and the universal coefficient of the logarithmic term in the entanglement entropy via a crossing-point analysis. For the shortest-range interacting case studied, we obtain the thermodynamic-limit value of the coefficient as $\tilde{c}=1.519\left(3\right)$, which is significantly smaller than values reported in previous studies.

Recent computational work evaluated the phase stability of ${\mathrm{UCo}}_2$ and ${\mathrm{UNi}}_2$ in the C14, C15, and C36 Laves phases and reported their computationally determined phonon density of states. To corroborate these computational findings, we report the experimentally determined phonon density of states for ${\mathrm{UCo}}_2$ and ${\mathrm{UNi}}_2$ using inelastic neutron scattering at the wide angular-range chopper spectrometer at the Spallation Neutron Source at Oak Ridge National Laboratory. We found excellent agreement between experimental and computational results for ${\mathrm{UNi}}_2$ and noted that some differences were observed for ${\mathrm{UCo}}_2$. By comparing the phonon density of states of ${\mathrm{UCo}}_2$ with that of other U-bearing Laves phases, we found that ${\mathrm{UCo}}_2$ showed distinct vibrational properties. From the one-phonon density of states, we calculated the lattice contribution to the specific heat of ${\mathrm{UNi}}_2$ and ${\mathrm{UCo}}_2$. Finally, we bound the electronic contribution to the specific heat in ${\mathrm{UNi}}_2$.

We explore the quantum pseudospin-1 pyrochlore magnet featuring ${\mathrm{Fe}}^{2+}$-based spinel oxides that addresses the formation of amplitude-modulated spin-density waves. We propose that the relatively small spin-orbit coupling and the small extra crystal field splitting in these materials create anisotropic exchange interactions and strong single-ion anisotropy, respectively, whose interplay becomes the source of quadrupolar moments selectively appearing on certain sublattices, leading to a spatially modulated hybrid of dipolar and quadrupolar moments. This mechanism represents the possibility of insulating magnets to form an exotic phase with coexisting liquid-solid properties.

A detailed study of electrical transport, magnetotransport, anomalous, and topological Hall effect behavior of van der Waals force bonded layered single-crystalline ${\mathrm{Fe}}_{3-x}{\mathrm{GeTe}}_2$ ($x\approx 0.3$) have been performed. The single crystal of ${\mathrm{Fe}}_{3-x}{\mathrm{GeTe}}_2$, grown by the chemical vapor transport method, crystallizes in hexagonal crystal structure with space group $\mathit{P}{6}_3/\mathit{mmc}$. Temperature ($T$)-dependent dc magnetic susceptibility of ${\mathrm{Fe}}_{3-x}{\mathrm{GeTe}}_2$ depicts a paramagnetic to ferromagnetic transition at $T\approx 180\mathrm{K}$ (${\mathit{T}}_{\mathrm{C}}$). Magnetic field variations of isothermal magnetization along the principal crystallographic directions in the magnetically ordered state at 5 K reveal soft ferromagnetic nature and significant magnetic anisotropy with the crystallographic $c$ axis being the easy axis of magnetization. Temperature-dependent study of linear electrical resistivity reveals the metallic nature of ${\mathrm{Fe}}_{3-x}{\mathrm{GeTe}}_2$, exhibiting different scattering phenomena in three consecutive temperature regimes. The quadratic temperature dependence of linear electrical resistivity of ${\mathrm{Fe}}_{3-x}{\mathrm{GeTe}}_2$ below the magnetic ordering temperature gives a clear indication of the dominance of electron-magnon scattering. Magnetoresistance of ${\mathrm{Fe}}_{3-x}{\mathrm{GeTe}}_2$ along both the principal crystallographic directions are found to be negative and unsaturated with varying magnetic fields. The nature of the magnetic field dependence of magnetoresistance is very unusual, however exotic, revealing significant anisotropic behavior. Field-dependent magnetoresistance along the hard magnetization direction depicts quadratic magnetization dependence till the saturation magnetization field, which is reminiscent of the chiral spin texture of skyrmion host material. The study of Hall effect in ${\mathrm{Fe}}_{3-x}{\mathrm{GeTe}}_2$ depicts an anomalous Hall behavior, as expected. In addition, Hall effect of ${\mathrm{Fe}}_{3-x}{\mathrm{GeTe}}_2$ depicts a signature revealing nontrivial topological spin texture when magnetic field and current were applied along the basal $ab$ plane, however perpendicular to each other. This type of topological Hall signature is expected for a candidate skyrmion host material like ${\mathrm{Fe}}_{3-x}{\mathrm{GeTe}}_2$.

We present a descriptor based on charge-induced atomic strain in crystalline lattices for predicting structural phase transformations in rare-earth intermetallic compounds containing lanthanides and transition metals. The charge-induced local atomic strain was obtained from structural optimization of experimentally known crystalline phases using state of the art density-functional theory methods. The predictive power of the descriptor was evaluated on $R{E}_2\mathrm{In}$ ($\mathit{RE}$ = rare earth) compounds, a class known for diverse phase transformations. We show that incorporating quantum-mechanical effects—such as local charge distribution, bonding, symmetry, and electronic structure—enhances the robustness of the descriptor. To gain further insight, we analyzed phononic and electronic behavior in ${\mathrm{Y}}_2\mathrm{In}$ and demonstrated that experimental phase transformations are captured only when atomic strain effects are included. The descriptor was further used to predict structural phase changes in ${\left(\mathrm{Y}{\mathrm{b}}_{1–x}\mathrm{E}{\mathrm{r}}_x\right)}_2\mathrm{In}$ and $\mathrm{G}{\mathrm{d}}_2\left(\mathrm{I}{\mathrm{n}}_{1–x}\mathrm{A}{\mathrm{l}}_x\right)$, with predictions confirmed by x-ray powder diffraction. While the current study is focused on lanthanide-based intermetallics, the underlying principles of the descriptor suggest potential applicability to other closely related classes of rare-earth intermetallics.

We theoretically study multiterminal transport in a setup consisting of two normal metal leads connected to a topological superconductor hosting one-dimensional dispersing Majorana edge modes. In the proposed system, the unpaired nature of the Majorana edge modes inherently leads to a strong suppression of the charge current in the linear response regime, while the current fluctuations remain significant. As a result, the noise-to-current ratio becomes substantially enhanced at low bias voltages, providing a clear signature of the dispersing Majorana edge modes. We reach this conclusion analytically, without relying on any specific model of topological superconductors. The predicted giant noise-to-current ratio is verified through numerical calculations using tight-binding models of topological-insulator-based topological superconductors. We also discuss the application of our proposal to the ${\mathrm{CoSi}}_2/{\mathrm{TiSi}}_2$ heterostructure and the iron-based superconductor ${\mathrm{FeTe}}_{1-x}{\mathrm{Se}}_x$.

The investigation of high-pressure effects on two-dimensional materials is pivotal for elucidating their distinctive properties and uncovering their potential applications, as pressure can dramatically modify their structural and electronic characteristics. Among these materials, the layered binary monochalcogenide GeS, being isoelectronic and isostructural to black phosphorus, demands an in-depth investigation to reveal its structural and electronic properties under high pressure, thereby enhancing our understanding and potential applications of binary IV-VI monochalcogenides. In this study, we systematically investigate the structural and electrical transport properties of monocrystalline GeS under extreme pressures, reaching approximately 200 GPa, through a combination of computational modeling and experimental techniques. Our findings reveal a phase transition from Pnma to the Cmcm structure at around 35 GPa, followed by a transition to a $Pm\overline{3}m$ structure around 90 GPa. Notably, we observe a metallic-superconductor transition at 44.5 GPa, with a critical temperature ($T_c$) of 3 K, representing experimental evidence of superconductivity in the Cmcm phase of binary IV-VI monochalcogenides. Remarkably, the superconducting behavior of GeS remains robust across the whole studied pressure range, achieving a maximum $T_c$ of 9 K at 193.6 GPa. Furthermore, during the decompression process, we observe an anomalous increase in $T_c$, reaching up to 11 K, highlighting the need for further exploration of other binary IV-VI monochalcogenides and advancing our understanding of superconductivity in layered materials for practical applications.

We report a coordinated Raman/computation study of the rare earth nitrides, a series of intrinsic ferromagnetic semiconductors, to reveal the presence of cation vacancies. Their presence is signaled by a Raman-active vibrational mode at 1100–1400 ${\mathrm{cm}}^{-1}$, rising steadily as the lattice contracts across the series. The mode's frequency is in excellent agreement with the computed breathing-mode vibration of the six nitrogen ions surrounding cation vacancies. The discovery of such cation vacancies opens the door for hole doping that has so far been lacking in the exploitation of rare earth nitrides.

We theoretically investigate the bilinear current, scaling as $j\sim EB$, in two- and three-dimensional systems. Based on the extended semiclassical theory, this bilinear current, including both longitudinal and transverse response, is classified according to their different scaling relations with the relaxation time. We reveal the distinct contributions to the ordinary Hall effect, the planar Hall effect, and magnetoresistance. We further highlight the spin contribution of an intrinsic ordinary Hall current, which has a geometric origin. Our theory is explicitly applied to study massive Dirac models and $\mathcal{PT}$-symmetric systems. The results demonstrate the capacity of the bilinear current to probe the band structure, specifically its ability to distinguish Weyl/Dirac points with different dispersions. Specifically, a tilt is necessary for the planar Hall effect (PHE) because of a symmetry constraint, and the orbital PHE only exist in the three-dimensional system. The $\tau$-scaling current vanishes due to $\mathcal{PT}$ symmetry. Finally, ${\tau }^0$- and $\tau$-scaling reveal their band-geometric nature, and they are enhanced near the small-gap region. Our work presents a theory of magnetotransport, potentially laying the groundwork for future experimental studies or device fabrications.

Studies of random unitary circuits have shown that the calculation of Rényi entropies of entanglement can be mapped to classical statistical mechanics problems in spacetime. In this paper, we develop an analogous spacetime picture of entanglement generation for random free or weakly interacting fermion systems without conservation laws. We first study a free-fermion model, namely a one-dimensional chain of Majorana modes with nearest-neighbor hoppings, random in both space and time. We analyze the $N\mathrm{th}$ Rényi entropy of entanglement using a replica formalism, and we show that the effective model is equivalent to an $\mathrm{SO}\left(2N\right)$ Heisenberg spin chain evolving in imaginary time. By applying a saddle-point approximation to the coherent states path integral for the $N=2$ case, we arrive at a semiclassical picture for the dynamics of the entanglement purity, in terms of two classical fields in spacetime. The classical solutions involve a smooth domain wall that interpolates between two values, with the width of this smooth domain wall spreading diffusively in time. We then study how adding weak interactions to the free-fermion model modifies this spacetime picture. Interactions reduce the symmetry of the effective continuum description. As a result the width of the entanglement domain wall remains finite, rather than growing diffusively in time. This yields a crossover from diffusive to ballistic spreading of information.

Altermagnets with nonrelativistic momentum-dependent spin splitting and compensated net magnetic moments have recently garnered significant interest in spintronics, particularly as pinning layers in magnetic tunnel junctions (MTJs). However, room temperature (RT) altermagnet-based MTJs with tunable tunneling magnetoresistance (TMR) or electroresistance (TER) modulated by multiferroicity remain largely unexplored. Here, we propose an experimentally fabricable above-RT multiferroic MTJ, comprising an altermagnetic metal, ferroelectric barrier, and ferromagnetic metal–epitomized by a $\mathrm{Cr}\mathrm{Sb}\text{/}{\mathrm{In}}_2{\mathrm{Se}}_3\text{/}{\mathrm{Fe}}_3\mathrm{Ga}{\mathrm{Te}}_2$ heterostructure. Our calculations with first-principles and nonequilibrium Green's function method indicate that the architecture enables magnetically switchable TER, electrically tunable TMR, and dual-mode controllable spin filtering. To disentangle the roles of ferroelectricity and the tunnel barrier, nonferroelectric $\mathrm{S}{\mathrm{b}}_2{\mathrm{Se}}_3$ and a vacuum gap are exploited as control cases. Remarkably, the system achieves TMR up to 2308%, TER of 707%, and near-perfect spin filtering efficiency. Both TMR and TER are considerable for $\mathrm{Cr}\mathrm{Sb}\text{/}{\mathrm{In}}_2{\mathrm{Se}}_3\text{/}{\mathrm{Fe}}_3\mathrm{Ga}{\mathrm{Te}}_2$ with either Cr or Sb interface. The transport performance is robust under bias voltage. These findings demonstrate the above-RT multiferroic altermagnet-based MTJs and highlight their exciting potential as a versatile platform for next-generation spin dynamics, magnetic sensing, and quantum logic nanodevices.

Topological superconductivity is currently one of the prime interests, given the properties of its exotic nature of chiral edge states. A broken time-reversal symmetry (TRS) is an essential ingredient in the recipe of a chiral edge state. The Haldane model is one of the many factors that can break TRS in a system. Thus we explore the possibility of topological superconductivity in the Haldane model under the influence of a conventional superconductor. The edge states originating from such recipes mostly remain outside the superconducting gap. Contrary to this, in the presence of spin-orbit coupling, the edge modes lie within the superconducting gap and can lead to a gapless state for some range of parameters. Moreover, we use band inversion and projection on the real-space lattice to confirm the topological and chiral nature of the obtained edge states.

By using scanning tunneling microscopy/spectroscopy, we investigate the electronic structure on the atomic scale near Zn impurities in ${\mathrm{Bi}}_2{\mathrm{Sr}}_2\mathrm{Ca}{\left({\mathrm{Cu}}_{1-x}{\mathrm{Zn}}_x\right)}_2{\mathrm{O}}_{8+\delta }$. In the Fourier-transformed differential-conductance image measured at zero bias, two characteristic spots are observed with the wave vectors of about 0.13($2\pi /a_0$) and 0.23($2\pi /a_0$), which correspond to the local density of states modulations with real-space periods of about eight unit cells ($8a_0$) and four unit cells ($4a_0$), respectively. We argue that the $8a_0$ modulation may be the consequence of a pair density wave (PDW), while the $4a_0$ modulation is the coexistent charge density wave or another PDW. The two modulations emerge exactly near the Zn impurities when the superconductivity is suppressed nearby, suggesting that the related phases may be the competing order of superconductivity. The $8a_0$ and $4a_0$ modulations have strong amplitudes near the Zn impurities. The effective range of the PDW modulation is similar to the scale of the Cooper-pair condensate, but much larger than that of the impurity resonance state of quasiparticles. In addition, both oscillations have the local maxima at Zn impurities, providing direct phase information of the two coexisting phases. Our results provide additional insight into the relationship between the superconducting coherent state and the PDW state in cuprates.