The devil's staircase (DS) phenomenon is a fractal response of magnetization to external fields, traditionally observed in periodic ferromagnetic systems, where the commensurability between spin arrangements, lattice parameters, and external magnetic fields governs abrupt changes in magnetization. Its occurrence in aperiodic, fractal-type systems has remained largely unexplored, despite their natural compatibility with such phenomena. Using a quantum annealing device, we uncover a wealth of abrupt magnetic transitions between spin manifolds driven by increasing external magnetic fields within a simple yet effective Ising-model framework. In contrast to periodic systems, where DS arises from long-range competing interactions, our findings reveal that short-range, purely antiferromagnetic couplings in aperiodic geometries produce equally rich ground-state magnetization patterns. We demonstrate that while magnetic textures are determined by the lattice size, their formation remains remarkably robust and independent of scale, with commensurability emerging locally. Our results challenge the prevailing view that DS behavior is limited to periodic systems and establish quasiperiodic geometries as a natural host for this phenomenon.

The Potts model describes interacting spins with $Q$ different components, which is a direct generalization of the Ising model ($Q=2$). Compared to the existing exact solutions in 2D, the phase transitions and critical phenomena in the 3D Potts model have been less explored. Here, we systematically investigate a quantum $(2+1)$-D Potts model with $Q=3$ using a fuzzy sphere regularization scheme. We first construct a microscopic model capable of achieving a magnetic phase transition that separates a spin $S_3$ permutationally symmetric paramagnet and a spontaneous symmetry-breaking ferromagnet. Importantly, the energy spectrum at the phase transition point exhibits an approximately conformal symmetry, implying that an underlying conformal field theory may govern this transition. Moreover, when tuning along the phase transition line in the mapped phase diagram, we find that the dimension of the subleading $S_3$ singlet operator flows and drifts around the critical value $\sim 3$, which is believed to be crucial for understanding this phase transition, although determining its precise value remains challenging due to the limitations of our finite-size calculations. These findings suggest a discontinuous transition in the 3D three-state Potts model, characterized by pseudocritical behavior, which we argue results from a nearby multicritical or complex fixed point.

This is a response to the Comment [Phys. Rev. B 111, 146401 (2025)] by Yokouchi et al. on our paper [Phys. Rev. B 110, 174402 (2024)]. In this Reply, we note that (i) their arguments lack a discussion of whether the overall characteristics of the observed nonlinear impedance, including its magnitude and unphysical negative inductance interpretation, can be explained by the emergent induction scenario, whereas the Joule heating model can, (ii) they incorrectly refer to the Joule heating model, and (iii) their new data in the Comment are also quantitatively explained by the Joule heating model. These findings suggest that, contrary to the opinion by Yokouchi et al., the overall behavior of the observed impedance is irrelevant to emergent induction.

Electrides represent a unique class of materials in which excess electrons are confined to interstitial sites within the crystal lattice rather than being bound to atomic nuclei. Here, we present ScAl—an existing metallic compound—as a three-dimensional electride with a nontrivial topological electronic structure. Via first-principles calculations, we demonstrate that ScAl qualifies as a zero-dimensional electride, with excess electrons occupying the $3d$ Wyckoff position in its lattice. Notably, the electronic bands near the Fermi level mainly originate from these excess electrons. A band inversion occurs among the bands near the Fermi level, leading to the formation of a nodal loop characterized by a drumhead surface state. We establish the effective model to characterize the nodal loop, revealing the symmetry protection mechanism. Due to the relatively weak spin-orbital coupling (SOC) in the excess electrons, the inclusion of SOC introduces a small gap at the nodal loop. Moreover, the topological and electride characteristics of ScAl are robust against external perturbations, such as strain and doping. Our findings expand the family of inorganic electrides and highlight the intricate interplay between electride chemistry and band topology, offering different avenues for exploration in this field.

Model lattices such as the kagome and Lieb lattices have been widely investigated to elucidate the properties of interacting flat-band systems. While a quasicrystal does not have proper bands, the noninteracting density of states of several of them displays the typical signature of a flat band pinned at the Fermi level: a delta-function zero-energy peak. Here, we employ quantum Monte Carlo simulations to determine the effect of onsite repulsion on these quasicrystals. While global properties such as the antiferromagnetic structure factor and the specific heat behave similarly as in the case of periodic lattices undergoing a Mott transition, the behavior of the local density of states depends on the coordination number of the site. In particular, sites with the smallest coordination number, which give the dominant spectral-weight contribution to the zero-energy peak, are the ones most strongly impacted by the interaction. Besides establishing site-selective correlations in quasicrystals, our work also points to the importance of the real-space structure of flat bands in interacting systems.

We present SCALINN—strongly correlated approach with language-inspired neural network—as a method for solving the Anderson impurity model and reducing the computational cost of dynamical mean-field theory calculations. Inspired by the success of generative Transformer networks in natural language processing, SCALINN utilizes an in-house modified Transformer network in order to learn correlated Matsubara Green's functions, which act as solutions to the impurity model. This is achieved by providing the network with low-cost Matsubara Green's functions, thereby overcoming the computational cost of high accuracy solutions. Across different temperatures and interaction strengths, the performance of SCALINN is demonstrated in both physical observables (spectral function, Matsubara Green's functions, quasiparticle weight), and the mean squared error cost values of the neural network, showcasing the network's ability to accelerate Green's function based calculations of correlated materials by predicting DMFT solver solutions, which—given a sufficiently comprehensive training database—can be applied across materials and regimes, enabling ab initio $\mathrm{DFT}+\mathrm{DMFT}$ calculations without prior knowledge of the material properties.

Cu/GaN heterointerfaces exist widely in electronic devices and constitute one of the primary thermal resistances. The intricate interfacial morphology and electron-phonon coupling effects pose significant challenges to the modeling of interfacial thermal transport. In this study, an advanced electron density–corrected two-temperature molecular dynamics (EDC-TTMD) framework combined with a fractal rough interface was developed to accurately capture electron-phonon coupling behaviors at rough interfaces. The model was first validated by available experimental data of three types of heterojunctions—Cu/diamond, Cu/BN, and Al/GaN. The thermal boundary conductance (TBC) predicted by present EDC-TTMD agrees more with experimental data than the nonequilibrium molecular dynamics results. Subsequently, Cu/GaN heterojunctions with various interfacial roughnesses were constructed and simulated. The results reveal that the TBC undergoes a rapid increase as the interfacial roughness increases and then decreases gradually after reaching a plateau. Finally, based on the thermal resistance analysis and phonon structure calculations, the enhancement of TBC at low interfacial roughness is primarily attributed to the introduction of electron-phonon transport channels, which was neglected in previous simulations. In contrast, the slight reduction in TBC at high interfacial roughness is primarily attributed to the enhanced phonon localization and interfacial scattering. This study establishes a novel framework for simulating electron-phonon coupled nonequilibrium thermal transport across metal/semiconductor heterojunctions with rough interfaces, providing insights into the regulation of thermal boundary conductance in such systems.

Nanoribbons derived from two-dimensional (2D) materials can exhibit extraordinary electronic properties that are not present in their monolayer counterparts. Fabricating nanoribbons of 2D materials with intrinsic collective electronic states and uncovering the underlying quantum confinement effects are fundamental concepts in both physics and nanotechnology. Monolayer $\mathrm{NbS}{\mathrm{e}}_2$ is a model system in this regard, as it has been proved to host a $3\times 3$ charge-density-wave ground state. However, discrete $\mathrm{NbS}{\mathrm{e}}_2$ nanoribbons have not been produced yet. Here, we successfully fabricate quantities of $\mathrm{NbS}{\mathrm{e}}_2$ nanoribbonlike structures, where the atoms spontaneously reconstruct into a $7\times 1$ stripe phase. Our spectroscopic measurements further reveal a unidirectional charge density modulation in $\mathrm{NbS}{\mathrm{e}}_2$ nanoribbonlike structures, with the charge states exhibiting an out-of-phase accumulation on the two sides of $-0.15$ V. These findings establish $\mathrm{NbS}{\mathrm{e}}_2$ nanoribbons as an intriguing platform for exploring one-dimensional-confined collective electronic states, offering a stepping stone toward nanoelectronic devices.

We present evidence of nontrivial topology in the kagome semimetal $\mathrm{N}{\mathrm{i}}_3\mathrm{I}{\mathrm{n}}_2{\mathrm{S}}_2$ from quantum oscillation experiments at high magnetic fields up to 31 T and theoretical investigations by first-principles calculations. Angle-dependent de Haas–van Alphen oscillations reveal the presence of quasi-two-dimensional hole and three-dimensional electron pockets, consistent with first-principles calculations, along with signatures of magnetic breakdown across these pockets. In particular, we find that the smallest cyclotron orbit, $F_{\alpha }\approx 10$ T, enclosing theoretically predicted endless Dirac nodal lines, has a relatively low effective mass of $0.183m_0$ and a Berry phase close to π. Furthermore, this orbit has a high quantum mobility of 0.88 ${\mathrm{m}}^2{\mathrm{V}}^{-1}{\mathrm{S}}^{-1}$, an order of magnitude larger than that of the heavier charge carriers. Infrared spectroscopy reveals linearly increasing optical conductivity with photon energy above 45 meV. These experimental results, as confirmed by first-principles calculations, support that massive Dirac fermions, formed by a small gap opening due to spin-orbit coupling, possess nontrivial topology and can contribute considerably to electrical transport. We also observe linear magnetoresistance above 12.7 T, which can be attributed to the quantum magnetoresistance of the Dirac fermions concentrated on the zeroth Landau level.

By using angle-resolved photoelectron spectroscopy (ARPES), we investigate the surface electronic structure of magnetic Weyl semimetal ${\mathrm{Co}}_3{\mathrm{Sn}}_2{\mathrm{S}}_2$ focusing around the $K$ points, where surface states related to Fermi arcs are predicted by density functional theory (DFT) calculations. The Fermi arc picture is sensitive to the different terminations (S, Sn, and Co). The surface states' connectivity between the Weyl points is not very clear in the S-terminated face contrary to the Sn and Co terminations, where the Fermi arcs are quite apparent exhibiting connectivity between the Weyl points located in the intra- and inter-Brillouin zones, respectively. We identify three surface states (SS1, SS2, and SS3) in our ARPES data showing resemblance to the DFT predicted surface states of S, Sn, and Co terminations. The SS2 is more robust in comparison to the SS3 against the changes developed by the thermal cycle and doping. This different behavior is possibly related to the different surface potential between the Sn- and Co-terminated surfaces. These results provide direct experimental insight about the variation of the surface state scenario among the three terminations as suggested by the DFT calculations, which could have implications on the Fermi arc stability occurring at the different surface terminations.

Recently, topological semimetals have emerged as strong candidates for solid-state thermomagnetic refrigerators due to their enhanced Nernst effect. This enhancement arises from the combined contributions of the Berry-curvature-induced anomalous Nernst coefficient associated with topological bands and the normal Nernst effect resulting from synergistic electron-hole compensation. Generally, these two effects are intertwined in topological semimetals, making it challenging to evaluate them independently. Here, we report the observation of a high Nernst effect in the electron-hole compensated semimetal ScSb with topologically trivial electronic band structures. Remarkably, we find a high maximum Nernst power factor of $P{F}_N\sim 35\times {10}^{-4}$ W ${\mathrm{m}}^{-1}{\mathrm{K}}^{-2}$ in ScSb. The Nernst thermopower $\left(S_{xy}\right)$ exhibits a peak of $\sim 47$ $\mu \mathrm{V}/\mathrm{K}$ at 12 K and 14 T, yielding a Nernst figure of merit $\left(z_N\right)$ of $\sim 28\times {10}^{-4}{\mathrm{K}}^{-1}$. Notably, despite its trivial electronic band structure, both the $P{F}_N$ and $z_N$ values of ScSb are comparable to those observed in topological semimetals with Dirac band dispersions. The origin of the large Nernst signal in ScSb is explained by compensated electron and hole carriers, through Hall resistivity measurements, angle-resolved photoemission spectroscopy, and density functional theory calculations.

We study the competition between the Ruderman-Kittel-Kasuya-Yosida (RKKY) quadratic and biquadratic spin-spin interactions of two magnetic impurities in twisted bilayer graphene away from the magic angle. We apply the Bistritzer-MacDonald model of two graphene layers twisted with respect to each other by a small angle. By reducing the model to the Dirac-type one with modified Fermi velocity, we derive expressions for the RKKY quadratic and biquadratic spin interactions using perturbation theory for the free energy. The biquadratic interaction is suppressed by a larger power of the interaction constant and decreases faster with the distance between impurities compared to the quadratic one. Nevertheless, due to the different period of the oscillations with the impurity separation distance, chemical potential, twist angle, and temperature, it is possible to fine-tune the system to the regime of dominating biquadratic interaction. The existence of such a fine-tuned regime might provide a promising opportunity to observe nonconventional spin ordering.

Understanding low-energy excitations in fermionic systems is crucial for their characterization. They determine the response of the system to external weak perturbations, its dynamical correlation functions, and provide mechanisms for the emergence of exotic phases of matter. In this work, we study the spin excitation spectra of the one-dimensional (1D) Fermi-Hubbard model using a digital quantum processor. Introducing a protocol that is naturally suited for simulation on quantum computers, we recover the retarded spin Green's function from the time evolution of simple observables after a specific quantum quench. We exploit the robustness of the protocol to perturbations of the initial state to minimize the quantum resources required for the initial state preparation, and to allocate the majority of them to a Trotterized time-dynamics simulation. This, combined with the intrinsic resilience to noise of the protocol, allows us to accurately reconstruct the spin excitation spectrum for large instances of the 1D Fermi-Hubbard model without making use of expensive error mitigation techniques, using up to 30 qubits of an IBM Heron r2 device.

Generating and controlling valley-contrasting Berry curvature in two-dimensional (2D) hexagonal magnetic materials holds significant promise for advancements in spintronics and valleytronics. Here, we explore the interplay between valley index, magnetic ordering, and band topology in a single 2D semi-half-metallic system, introducing a critical state termed valley-semi-half-metal, which is crucial for realizing high Chern number quantum anomalous Hall (QAH) insulators. We identify the fluorinated $1\mathrm{T}\text{−}{\mathrm{CrS}}_2$ monolayer ($1\mathrm{T}\text{−}{\mathrm{CrS}}_2{\mathrm{F}}_2$) as a promising material, exhibiting soft ferromagnetic characteristics ideal for achieving this 2D valley-semi-half-metallic state. Remarkably, the monolayer $1\mathrm{T}\text{−}{\mathrm{CrS}}_2{\mathrm{F}}_2$ can transition from a semi-half-metallic state to a high Chern number QAH insulator with opposite-chiral edge states through magnetization reversal. Additionally, the Janus $1\mathrm{T}\text{−}{\mathrm{CrS}}_2\mathrm{FCl}$ monolayer, which lacks inversion symmetry, enables gate-tunable, valley-contrasting QAH insulator phases with opposite Chern numbers upon reversing the magnetization. Our findings highlight a promising magnetic candidate for exploring valley and topological physics, offering an alternative approach for designing switchable QAH effects and paving the way for innovative topological quantum devices.

The ordered vacancy compounds $A{M}_2{X}_4$ have gained significant attention in thermoelectric research due to their promising electrical and thermoelectric properties. In this work, we present a first-principles-based high-throughput approach to screen 450 ordered vacancy compounds $A{M}_2{X}_4$ for potential thermoelectric applications. Initial screening criteria such as band gap, stability, and Pugh's ratio, followed by the phonon spectrum analysis through interception frequency, were used to identify promising candidates, highlighting a strong correlation between lattice thermal conductivity and Pugh's ratio. Despite sharing similar crystal structure of $\mathrm{Mg}{M}_2{\mathrm{Te}}_4$ $(\mathrm{M}=\mathrm{Sc}, \mathrm{Y}, \mathrm{Ga}, \text{and} \mathrm{In})$, ${\mathrm{MgY}}_2{\mathrm{Te}}_4$ exhibits an exceptionally low lattice thermal conductivity of 0.12 W/mK, in stark contrast to ${\mathrm{MgGa}}_2{\mathrm{Te}}_4$ (6.88 W/mK). This discrepancy is attributed to the significantly weaker bonding strength of Sc/Y-Te compared to Ga/In-Te, which enhances lattice anharmonicity and phonon scattering. Additionally, candidate materials with ultralow lattice thermal conductivity are characterized by low-frequency phonons contributing <2 THz, among which ${\mathrm{MgY}}_2{\mathrm{Te}}_4$ demonstrates excellent thermoelectric performance with a maximum ZT of ∼4.7. This work not only unravels the importance of strong anharmonicity and phonon scattering induced by weak-bonded heavy elements on the thermoelectric performance in the $A{M}_2{X}_4$ family, but also showcases that the screening through Pugh's ratio and interception frequency is an effective strategy for discovering high-performance flexible thermoelectric materials.

The discovery of two-dimensional (2D) ferroelectric materials has prompted the study of thin ferroelectric heterostructures for advanced functional device applications. Based on the first-principles density functional theory, we investigate the twist-angle-dependent ferroelectricity and ferromagnetism of 2D ferroelectric ${\mathrm{In}}_2{\mathrm{Se}}_3$/ferromagnetic ${\mathrm{CrBr}}_3$ twisted moiré heterobilayers. We show that, as the twist angle increases, the stronger structural distortions induced by the moiré pattern cause more changes in charge transfers, thus consistently affecting the ferroelectricity and ferromagnetism of heterobilayers. We also show that structural distortions and their induced charge transfer determine the changing tendency of band edges and band gaps with respect to the twist angle. Our findings provide fundamental knowledge of the effects of the twist-angle-dependent moiré pattern on the ferroelectric and ferromagnetic heterobilayer and facilitate the development of ferroelectric magnetic devices.

Carbon nanodots (CNDs) are surface-passivated fluorescent nanomaterials which can be potentially applied for, e.g., full-color lighting and displays. Here, we present a pioneering study on magneto-optical properties of nitrogen-doped CNDs (N-CNDs) using terahertz (THz) time-domain spectroscopy in the presence of the magnetic fields from 0 to 8 T at a fixed temperature of 80 K. In the Faraday geometry and applying the optical polarization tests, we can measure the real and imaginary parts of the left- and right-handed circularly polarized magneto-optical conductances for a thin N-CND layer on a sapphire substrate, which can fit well with the magneto-optical Drude-Smith formula we previously generalized. By fitting the experimental data with the theoretical model, we can determine magneto-optically the key electronic parameters of N-CND layer, such as the electron density related coefficient $\gamma$, the electronic relaxation time $\tau$, the photon-induced electronic localization factor $\alpha$, and particularly, the effective electron mass $m^{*}$ obtained under noncyclotron resonance condition. The impact of the magnetic field on these parameters is investigated. We find that the presence of the magnetic field can result in smaller $\gamma$ and $\alpha$, heavier $m^{*}$, and longer $\tau$ in the N-CND layer. The outcomes of this work are valuable in providing us with a deeper understanding of the basic electronic properties of N-CNDs.

Altermagnetism has extended the magnetic landscape beyond conventional ferromagnetism and antiferromagnetism. Here, we report a general scheme to realize phase transitions between ferromagnetism and altermagnetism, as well as between antiferromagnetism and altermagnetism, in various two-dimensional magnetic systems. Specifically, we predict a series of $A_{2}M{X}_4$-related ($A=3d$ transition metals; $M=\mathrm{W}$ or Mo; $X=\mathrm{S}$, Se) materials that exhibit diverse magnetic ground states, including ferromagnetism, antiferromagnetism, and altermagnetism. Through interlayer sliding methods, interlayer exchange coupling in bilayer $A_{2}M{X}_4$ can be effectively controlled and switched between ferromagnetic and antiferromagnetic coupling, thus realizing an intrinsic phase transition between different magnetic orders, as exemplified by bilayer ${\mathrm{V}}_2\mathrm{Mo}{\mathrm{S}}_4$, $\mathrm{F}{\mathrm{e}}_2\mathrm{Mo}{\mathrm{S}}_4$, and $\mathrm{MnP}{\mathrm{S}}_3$. More interestingly, we show that layer-dependent phase transition from ferromagnetism to altermagnetism and from antiferromagnetism to altermagnetism can be tailored in the representative ${\mathrm{V}}_{2}M{X}_4$ and $\mathrm{F}{\mathrm{e}}_{2}M{X}_4$ due to interlayer exchange coupling breaks and preserves certain combined symmetries. Our results extend the concept of experimentally observed layer-dependent ferromagnetic-to-antiferromagnetic phase transitions, as seen in systems such as $\mathrm{Cr}{\mathrm{I}}_3$ and $\mathrm{MnB}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_4$. These findings highlight the facile transitions between the recorded magnetic phases, providing insights into the manifestation of altermagnetic properties in two-dimensional lattice, which opens avenues for designing new spintronic devices through layer effect.