We present a class of dynamical quantum instability in driven magnets leading to emergent enhancement of antiferromagnetic correlations even for purely ferromagnetic microscopic couplings. A primary parametric amplification creates a frequency-tuned nested magnon distribution in momentum space, which seeds a secondary instability marked by the emergence of enhanced antiferromagnetic correlations, mirroring the instability of nested Fermi surfaces in electronic systems. In sharp contrast to the fermionic case, however, the magnon-driven instability is intrinsically nonequilibrium and fundamentally inaccessible in thermal physics. Its quantum-mechanical origin sets it apart from classical instabilities such as Faraday and modulation instabilities, which underlie several instances of dynamical behavior observed in magnetic and cold-atom systems.

An electronic nematic order that originates from superconducting fluctuation but persists above the superconducting transition temperature is often referred to as a vestigial nematic phase. Such a vestigial order belongs to the broader class of composite orders discussed in earlier literature, characterized by ordering in gauge-invariant combinations of superconducting order parameters while the individual superconducting order parameters remain disordered. These states include metallic superfluids, paired phases, and composite (charge-$4e$) superconductors. Whether and under what conditions such a vestigial phase can emerge in realistic models of nematic superconductors remains an open question. Recent analytical work [P. T. How and S. K. Yip, Phys. Rev. B 107, 104514 (2023)] concluded that vestigial nematic phases—and related mechanisms—do not appear in the widely studied models proposed for, e.g., ${\mathrm{Bi}}_2{\mathrm{Se}}_3$-based candidates. To shed light on this question, we perform large-scale Monte Carlo simulations of a three-dimensional Ginzburg-Landau model of a nematic superconductor. Consistent with the findings of How and Yip, our numerical results confirm that commonly considered models do not exhibit vestigial nematic phases or nematic-fluctuation-induced charge-$4e$ superconductivity. Extending the analysis to include coupling to a gauge field, we show that vestigial nematic order can, under restrictive conditions, be stabilized through an alternative mechanism: intercomponent coupling mediated by the gauge field or the effects of strong correlations.

Inducing superconducting correlations in quantum anomalous Hall (QAH) states offers a promising route to realize topological superconductivity with chiral Majorana edge modes. However, the definitive identification of these modes is challenging. Here, we propose detecting superconducting chiral edge modes via the probability distribution of the resistance, or equivalently the charge transmission of QAH-superconductor heterojunctions. Remarkably, the distribution for coherent edge exhibits distinct characteristics for different topological superconducting phases in sufficiently long junctions, and this difference remains robust against weak decoherence. These findings provide insights into transport phenomena beyond the clean limit and highlight the resistance distribution as a compelling signature for distinguishing topological superconducting phases.

Herein, we propose a strategy to dramatically enhance negative linear compressibility (NLC) by lessening the multiplicity of nets in materials whose crystal structures consist of multifold interpenetrating identical nets. Density functional theory calculations for $\mathrm{Zn}M{\left(\mathrm{CN}\right)}_4$ $(M=\mathrm{Ni}, \mathrm{Pd}, \mathrm{Pt})$ and Cu(tcm) $(\mathrm{tcm}=\mathrm{tricyanomethanide})$ constructed separately by multi- or single-net structures show that a reduction in the number of interpenetrating nets in a structure will dramatically increase the NLC value. Compared to multinet $\mathrm{Zn}M{\left(\mathrm{CN}\right)}_4$ and Cu(tcm), the NLC values of single-net $\mathrm{Zn}M{\left(\mathrm{CN}\right)}_4$ and Cu(tcm) are 4–5 times larger than those of multinet ones. Especially, single-net Cu(tcm) exhibits large NLC with a value of $-100.18\mathrm{TP}{\mathrm{a}}^{-1}$, which is the strongest NLC ever reported. This enhancement is attributed to the increased structural flexibility and larger open spaces that allow more significant deformation of frameworks under pressure. Additionally, these materials exhibit excellent optical transparency in the visible to infrared regions and hence are suitable for high-pressure optical applications. Our approach opens an effective way for designing materials with a large NLC effect.

Emerging altermagnetism provides a crystal symmetry foundation for spin manipulation by understanding the interaction between the altermagnetic ordering and elementary excitations in the 2D limit. In this study, we employ real-time time-dependent density functional theory (rt-TDDFT) and ab initio nonadiabatic molecular dynamics (NAMD) to investigate the out-of-equilibrium laser-induced spin dynamics in an altermagnetic semiconductor MnTe monolayer. During laser irradiation, our findings reveal a negligible electron-phonon coupling (EPC) between opposite spin sublattices. The excited spin-up Mn-$d$ electrons hop to spin-down Mn-$d$ orbitals through spin-orbit coupling (SOC) with a spin flip. Moreover, hexacoordinated $\mathrm{M}{\mathrm{n}}_{\mathrm{B}}$ atoms in the middle layer exhibit a more pronounced EPC compared to tetra-coordination $\mathrm{M}{\mathrm{n}}_{\mathrm{A}}$ atoms in the surface, leading to the photodriven asymmetric demagnetization dynamics and uncompensated net moment. Both EPC and SOC introduce channels for spin transfer from Mn to Te atoms, denoted as the optical-induced intersite spin transfer (OISTR) effect. Driving by asymmetric demagnetization and OISTR effect, our results indicate that altermagnetic state can reversibly transform into a metastable ferrimagnetic state via controlling laser pulse. After laser termination, excited $\mathrm{M}{\mathrm{n}}_{\mathrm{A}}-d$ electrons quickly decay to $\mathrm{M}{\mathrm{n}}_{\mathrm{B}}$ due to opposite spin $d-d$ SOC and then relax to spin-down Te-$p$ orbitals via EPC to recombine with holes. These dual relaxation channels significantly accelerate the spin flipping process and promote the altermagnetic-ferrimagnetic phase transition within a time scale of 246 fs. The reversible switching of the magnetic ordering provides a significant insight for the development of ultrafast optical switches in spintronics.

We extend the study of topological magnetisms to quasi-one-dimensional chiral geometries, revealing a symmetry-guided pathway to Dzyaloshinskii–Moriya interactions (DMI) and enabling the design of high-density spintronic devices. Utilizing symmetry analysis, a general strategy is proposed for inducing Bloch-type DMI in chiral geometries warped by low-dimensional magnets. By combining first-principles calculations, we demonstrate our concept in various chiral geometries, e.g., chiral nanoribbon and nanotubes, which are composed of quasi-one-dimensional ${\mathrm{CrBr}}_2$ nanoribbon and two-dimensional magnets with different crystal symmetries, including CrN, transition metal dichalcogenides, VSe, ${\mathrm{CrI}}_3$, and ${\mathrm{Cr}}_2{\mathrm{Se}}_3$. More interestingly, we find that the chirality of Bloch-type DMI can be closely coupled with the helical direction of the chiral geometry. Our atomistic spin dynamics study using Monte Carlo simulation is performed on chiral ${\mathrm{VS}}_2$ nanotube as an example, in which Bloch-type domain walls with opposite chirality arising from Bloch-type DMI can be stabilized via opposite chirality indices (n, m) and (m, n). Our results that chiral geometry induces DMI in a broad range of 2D magnets, enabling topological magnetisms, pave the way for the development of geometry-driven spintronic devices.

Monolayer ${\mathrm{NiBr}}_2$ exhibits strain-tunable topological magnetism mediated by competing exchange interactions on a triangular lattice. Our first-principles calculations show biaxial strain ($\varepsilon$) controls both the exchange frustration strength $\eta =|J_1/J_3|$ and magnetic anisotropy energy, with Br-driven spin-orbit coupling flipping the magnetic easy axis at $\varepsilon =2\%$. In addition, the spin dynamics simulations reveal how strain-enhanced frustration nucleates domain walls that fragment into high-topological-charge skyrmions ($Q>1$) under out-of-plane magnetic fields. Deterministic switching between skyrmions and bimeron pairs textures emerges via coordinated in-plane/out-of-plane magnetic fields, while a universal topological collapse beyond a magnetic field $B>1.8$ T confirms Zeeman energy dominance. This strain-frustration-anisotropy interplay establishes a control paradigm for exotic spin topologies in two-dimensional magnets.

In this work, we explore the possible emergence of superconducting phases in a multi-Weyl semimetal. In particular, we show that the presence of a pair of Weyl nodes with chirality $\left|\nu \right|\ge 1$ leads to an effective description of the intranodal pairings in terms of monopole harmonics, in contrast to internodal pairings that preserve the angular dependence of conventional spherical harmonics. Therefore, we explore the conditions for the competition and/or coexistence between both types of superconducting phases, and we identify the presence of the so-called topological repulsion mechanism, which was previously reported in the context of simple Weyl semimetals. We identified the critical temperatures corresponding to the monopole and conventional superconducting phases, and calculated the specific heat as a function of temperature, thus showing that this thermodynamical parameter may provide an experimental probe to determine the chirality index $\nu$ in the material.

We demonstrate that a recent proposal for simulating planar hyperbolic lattices using circuit quantum electrodynamics can be extended to include higher-dimensional lattices in both Euclidean and non-Euclidean spaces by allowing circuits that involve more than three polygons at each vertex. The quantum dynamics of these circuits, which we are developing with current technology, are governed by effective tight-binding Hamiltonians that correspond to higher-dimensional Kagomé-like structures (such as $n$-dimensional zeolites). These structures are known for exhibiting strong frustration and flat bands. We analyze the spectra of both hyperbolic and positive-curvature lattices and derive exact expressions for the fraction of flat-band states. Our findings significantly broaden the possibilities for realizing non-Euclidean geometries using circuit quantum electrodynamics, a research direction we are actively pursuing in microwave-guide circuits constructed with sputtered niobium films on silicon substrates.

It is well known that disorder can induce low-energy Andreev bound states in a sign-changing, but fully gapped, superconductor at $\pi$ junctions. Generically, these excitations are localized. Starting from a superconductor with a sign-changing and nodeless order parameter in the clean limit, here we demonstrate a mechanism for increasing the localization length associated with the low-energy Andreev bound states at a fixed disorder strength. We find that the Fubini-Study metric associated with the electronic Bloch wave functions controls the localization length and the hybridization between bound states localized at distinct $\pi$ junctions. We present results for the inverse participation ratio, superfluid stiffness, site-resolved, and disorder-averaged spectral functions as a function of increasing the Fubini-Study metric, which indicate an increased tendency towards delocalization. The low-energy properties resemble those of a dirty nodal superconductor with gapless Bogoliubov excitations. We place these results in the context of recent experiments in moiré graphene superconductors.

High-order sideband generation (HSG) in a one-dimensional direct-gap semiconductor offers new opportunities for attosecond spectroscopy and ultrafast band-structure control. However, conventional interpretations often neglect strong-field–induced band renormalization. Here, we demonstrate that (i) pump-strength–dependent sideband frequency shifts—referenced to the excitation frequency—provide direct evidence of Floquet band dressing, and (ii) sideband-yield modulation furnishes an instantaneous measure of the Floquet band-gap shift with few-meV resolution. We develop a framework to extract both the renormalized band edge and the avoided-crossing gap ${\tilde{\mathrm{\Delta }}}_2$, and we clarify the symmetry-imposed selection rules for odd and even sidebands, arising from simultaneous parity and energy conservation under bichromatic driving. These results establish terahertz-driven HSG as a phase-sensitive, high-resolution probe of light-engineered band structure in quantum materials.

Authors of recent studies have shown that the chiral anomaly (CA) is not limited to Weyl semimetals but is also shown by a larger class of materials called spin-orbit-coupled noncentrosymmetric metals (SOC-NCMs), which has shed more insight into the origin of the CA as a Fermi surface property rather than a nodal property. In this study, we explore nonlinear transport responses in SOC-NCMs within the framework of semiclassical dynamics, employing the Maxwell-Boltzmann transport theory augmented by charge conservation and momentum-dependent scattering processes. We consider both nonmagnetic and magnetic impurity scattering mechanisms. We demonstrate that the CA-induced nonlinear Hall (CNLH) response exhibits a characteristic quadratic dependence on the applied magnetic field and remains negative for both types of impurities. We find that magnetic scatterers leading to enhanced or suppressed interband scattering modify the magnitude of the signal but do not affect its qualitative behavior. In contrast, the presence of tilt in the band dispersion induces a pronounced anisotropic response, including a magnetic field direction-dependent sign reversal that can be categorized into weak and strong regimes. Furthermore, the CNLH response shows substantial directional anisotropy governed by the relative orientation of the external magnetic field and the tilt vector. Our findings will be helpful in designing the experimental setup to get direction-dependent conductivity, which can be tuned externally with the help of magnetic impurity sites.

Lateral heterostructures of two-dimensional (2D) materials provide an atomically coherent platform to study interfacial electronic structures. However, the influence of different interfacial bonding regimes on local electronic states remains unclear. Here, we perform a comparative study of three InSe-based lateral heterostructures formed with Au (metal), Sb (semimetal), and ${\mathrm{Sb}}_2{\mathrm{Se}}_3$ (semiconductor). Scanning tunneling microscopy and spectroscopy combined with first-principles calculations reveal distinct interfacial bonding and corresponding electronic reconstructions. In the Au/InSe heterostructure, strong orbital hybridization and charge transfer lead to metallic behavior and a reduced local band gap. The Sb/InSe interface exhibits moderate coupling with spatially separated valence- and conduction-band edges, characteristic of type-II alignment. In contrast, the ${\mathrm{Sb}}_2{\mathrm{Se}}_3/\mathrm{InSe}$ heterostructure shows nearly van der Waals–type bonding and preserves the intrinsic InSe band edges. By comparing charge-density difference, electrostatic potential profiles, and local density of states, we establish a clear correspondence between interfacial bonding character and electronic reconstruction. This study provides a microscopic understanding of how interfacial chemistry governs the electronic properties of 2D lateral heterostructures.

Cuprous tellurides $\left({\mathrm{Cu}}_{2-x}\mathrm{Te}\right)$ have recently garnered attention due to their multiple commensurate charge density wave (CDW) transitions. To elucidate the nature of these phase transitions, we investigated single-crystalline ${\mathrm{Cu}}_{2-x}\mathrm{Te}$ $(x\sim 0.1)$ using temperature-dependent measurements of specific heat $\left(C_{\mathrm{P}}\right)$, electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (κ). Two distinct anomalies were identified, one near room temperature $\left(T_{\mathrm{CI}}\right)$ and another $\sim 150\mathrm{K}$ $\left(T_{\mathrm{CII}}\right)$, accompanied by thermal hysteresis, indicative of the first-order nature of these transitions. Metastable states that arise from the pinning of the CDW domain lead to irreversibility between $T_{\mathrm{CI}}$ and $T_{\mathrm{CII}}$ during cooling and warming, which is likely driven by intrinsic Cu vacancies and associated lattice strain. At $T_{\mathrm{CI}}$, a sharp $C_{\mathrm{P}}\left(T\right)$ peak with a modest entropy release signifies that the transition is primarily dominated by strong electron–phonon coupling and partial electronic condensation. In contrast, the weaker anomaly in $C_{\mathrm{P}}\left(T\right)$ at $T_{\mathrm{CII}}$ suggests predominantly lattice-driven dynamics, possibly involving a soft mode. The $\rho \left(T\right)$ data reveal electron-electron correlations at low temperatures and metal-to-metal-like CDW transitions, likely involving partial Fermi surface gapping. The S(T) displays multiple sign reversals and anomalous enhancements across both transitions, indicating complex multiband transport due to CDW-induced Fermi surface reconstruction. A marked suppression in κ(T) at $T_{\mathrm{CI}}$ with competing electronic and phononic effects provides further evidence of strong electron-phonon interactions. Additionally, a kink near $T_{\mathrm{CII}}$ supports the involvement of soft phonon modes and highlights the role of lattice dynamics. A comparative analysis with other CDW materials contextualizes these findings and emphasizes the potential of ${\mathrm{Cu}}_{2-x}\mathrm{Te}$ for thermoelectric applications.