Kitaev magnets have emerged as pivotal systems for investigating frustrated magnetism, providing a unique platform to explore quantum phases governed by the interplay between bond-dependent anisotropy and external magnetic fields. However, the quantum phase diagrams, particularly near the dominant antiferromagnetic Kitaev regime, remain puzzling despite extensive studies. In this work, we perform unbiased exact diagonalization calculations of the Kitaev-$\mathrm{\Gamma }$ model in a [111] magnetic field on a $C_6$-symmetric 24-site cluster. By calculating the ${\mathbb{Z}}_2$ flux density and the topological entanglement entropy, we reveal multiple phase transitions and identify signatures of both scalar and vector chiral orders in the intermediate-field regime between the Kitaev spin liquid and the polarized phase. As the negative $\mathrm{\Gamma }$ interaction increases, we discover a proximate quantum spin liquid featured by a three-peak specific heat and a spin-flop phase at a moderate magnetic field. Our findings provide insight into the field-induced intermediate phases in the antiferromagnetic Kitaev model and pave the way for the hunt for emergent phases in real materials.

We present a systematic first-principles study of phonon-limited transport in the TaAs family of Weyl semimetals using the ab initio Boltzmann transport equation. The calculated electrical conductivities show excellent agreement with experimental data for high-quality samples, confirming that transport in these systems is predominantly limited by phonon scattering. Among the four compounds, NbP achieves the highest conductivity, governed primarily by its large Fermi velocities that offset its stronger scattering rates. In contrast, TaAs displays the lowest conductivity, linked to reduced carrier pockets and limited carrier velocities. Additionally, NbP conductivity remains largely unaffected by small hole or electron doping, whereas TaAs exhibits pronounced electron-hole asymmetry. NbAs and TaP show intermediate behavior, reflecting their Fermi-surface topologies and scattering phase space. These findings provide microscopic insight into the transport mechanisms of the TaAs family and emphasize the critical role of phonons, doping, and carrier dynamics in shaping their electronic response.

The evolution of thermodynamic properties through the interconvertibility process between Lieb and kagome lattices is explored in the presence of a magnetic field and intrinsic spin-orbit coupling (ISOC). Both lattices share similar crystallographic characteristics that allow for description by a generic tight-binding model with one control parameter $\theta$ mapping the transition lattice stages ($\pi /2\le \theta \le 2\pi /3$), being Lieb ($\theta =\pi /2$) and kagome ($\theta =2\pi /3$) the limiting cases. The magnetic field applied perpendicularly to the monolayer Lieb-kagome system causes a Zeeman splitting of the band structure, and the ISOC lifts the band degeneracy. The density of states, band structures, specific heat, static spin susceptibility, internal energy, and Helmholtz energy are computed for different temperature values, magnetic field amplitudes, and ISOC strengths through the various evolutionary stages of Lieb-kagome lattices. Our numerical calculations show (i) a metal-to-semiconductor phase transition induced by the applied magnetic field for the case of non-null ISOC; (ii) that the Schottky peak increases its intensity the higher the magnetic field amplitude and also when the $\theta$ value increases between Lieb to kagome lattices; (iii) that the paramagnetic susceptibility at low temperature is strongly $\theta$ dependent, exhibiting lower values the higher the $\theta$ value; and (iv) that kagome lattice presents the lower internal energy at $T=0$, meaning to be the most stable thermodynamically investigated structure between the interconvertible lattices in the range from Lieb to kagome.

In this study we have derived an exact framework for the calculation of the heat flux and its spectral decomposition in molecular dynamics (MD) for arbitrary many-body potentials. This work addresses several deficiencies and limitations of previous approaches and allows for the accurate computational study of thermal properties in a wide variety of many-body systems with MD. We have tested our modifications with Green-Kubo (GK) and nonequilibrium MD (NEMD) simulations for various two- and three-dimensional (2D and 3D) material systems using the Tersoff and Stillinger-Weber (SW) potentials as examples. The spectral decomposition of the heat current was also calculated for monolayer graphene (1LG) and ${\mathrm{MoS}}_2$, for different system lengths. Our results show that the heat current calculated by our method is consistently in agreement with the thermostat current in NEMD, while previous implementations can estimate quite poorly the thermal conductivity both under GK and NEMD simulations, and both for 2D and 3D materials. The decomposition of the heat current also sheds light on the contribution of different phonon modes to thermal conductivity and its dependence on length. Our methodology is implemented in the widely used lammps code specifically for the Tersoff and SW potentials, and it is readily applicable to the vast majority of many-body MD potentials.

Two-dimensional (2D) magnetic materials provide an ideal platform for atomic-scale engineering of both structural and magnetoelectric (ME) properties. Through first-principles density functional theory calculations, we systematically investigate the magnetic and electronic properties of monolayer ${\mathrm{Cr}}_2{\mathrm{Si}}_2{\mathrm{Te}}_6, {\mathrm{Cr}}_2{\mathrm{Si}}_2{\mathrm{Se}}_6$, Janus-type ${\mathrm{Cr}}_2{\mathrm{Si}}_2{\mathrm{Te}}_3{\mathrm{Se}}_3$, and ${\mathrm{Cr}}_2{\mathrm{Si}}_2{\mathrm{Te}}_6-{\mathrm{MoSe}}_2$ heterostructures under vertical electric fields. Remarkably, both the Janus structure (${\mathrm{Cr}}_2{\mathrm{Si}}_2{\mathrm{Te}}_3{\mathrm{Se}}_3$) and the heterostructure $\mathrm{C}{\mathrm{r}}_2\mathrm{S}{\mathrm{i}}_2\mathrm{T}{\mathrm{e}}_6-\mathrm{MoS}{\mathrm{e}}_2$ demonstrate more than tenfold enhancement in magnetocrystalline anisotropy energy tunability compared to pristine ${\mathrm{Cr}}_2{\mathrm{Si}}_2{\mathrm{Te}}_6$. This dramatic enhancement originates from symmetry-breaking effects: in pristine ${\mathrm{Cr}}_2{\mathrm{Si}}_2{\mathrm{Te}}_6$ and ${\mathrm{Cr}}_2{\mathrm{Si}}_2{\mathrm{Te}}_6$ monolayers, the inherent mirror symmetry leads to cancellation of net ME responses, whereas in the engineered asymmetry in Janus and heterostructure systems, subsurface layers play a predominant role in ME effects. These fundamental insights not only advance our understanding of 2D ME phenomena but also provide a clear design strategy for developing next-generation, electric-field-tunable spintronic devices.

Periodic driving provides a powerful tool towards Floquet engineering topological states with high tunability. Here, we theoretically demonstrate a dynamic route to engineer a Floquet higher-order Weyl semimetallic phase under the irradiation of periodic light fields. Based on first-principles calculations and the Floquet theorem, we uncover that circularly polarized light can induce a topological phase transition from a higher-order nodal line semimetal into a higher-order Weyl semimetal in three-dimensional graphdiyne. This higher-order Weyl semimetallic phase possesses two pairs of higher-order Weyl points, whose positions are precisely tunable via the incident light intensity. The higher-order topology is confirmed by two-dimensional surface Fermi arc states and one-dimensional hinge states, connecting Weyl points with opposite chirality. Our findings not only establish a realistic platform for studying Floquet engineering topological states but also open an avenue for the experimental observation of exotic higher-order Weyl physics.

We present a comprehensive theoretical analysis of magnetic heterostructures composed of ferromagnetic (FM) layers interfaced with three-dimensional topological insulators (TIs). Integrating out the topological surface states and computing the spin determinant to second order in spins, we derive the effective generalized Ruderman–Kittel–Kasuya–Yosida (RKKY) exchange interactions mediated by topological surface states. These interactions inherently incorporate spin-momentum locking and anisotropic spin susceptibilities stemming from the Dirac-like dispersion of the TI surface electrons. The analysis reveals that the interplay between the spin-orbit coupling intrinsic to the TI and the magnetization in the FM layer induces highly nonlocal and retarded, chiral, and Dzyaloshinskii-Moriya (DM)-like contributions to the effective spin Hamiltonian. Furthermore, the spin dynamics is studied through a derivation of the LLG equation for this problem. The induced interactions renormalize many of the FM's intrinsic properties, but a new term in the LLG equation is induced that is related to the rate of change of the magnetization's curl, which is relevant to skyrmion dynamics. The magnon dispersion exhibits modifications due to the TI-mediated interactions, including a softened inertial spin-wave mode and tunable magnon gaps, sensitive to a tunable chemical potential and interfacial exchange coupling strength. The results also apply to finite temperatures. They elucidate topologically induced magnetic phenomena and pave the way for engineering exotic spin textures, such as skyrmions and chiral domain walls, in TI-FM hybrid systems with tunable interactions.

Heavy rare-earth-based quaternary double perovskite with the formula $R_{2}B{B}^{\prime }{\mathrm{O}}_6$ has attracted great attention due to its multiple magnetic exchange interactions, intriguing type of magnetic ordering, and antisite disorder. In this work, magnetic behaviors, magnetic-field-assisted switching effect, and associated exchange interactions in Mn self-doped double perovskites $\mathrm{G}{\mathrm{d}}_2\mathrm{N}{\mathrm{i}}_{2-x}\mathrm{M}{\mathrm{n}}_x{\mathrm{O}}_6 (1.0\le x\le 1.6)$ are investigated by using different protocols of DC and AC magnetic measurements. Experiments indicate that negative magnetization effects characterized by $M_{\mathrm{FC}}<0$ under moderate positive magnetic fields are observed from $x=1.3$ up to $x=1.5$. The repeatability of $M$($T$) under different magnetic fields and its mirror symmetry about the temperature axis under $\pm H_{\mathrm{cool}}$ signify the intrinsic nature of the effect. The manipulability of magnetization polarity is demonstrated by the magnetic-field-assisted switching effect, indicating promising application prospects in spintronics devices. The simultaneous decrease of both $M_{\mathrm{FC}}$ and transition temperature $T_{\mathrm{C}}$ by Mn self-doping suggests the weakening of $\mathrm{N}{\mathrm{i}}^{2+}\text{−}\mathrm{M}{\mathrm{n}}^{4+}$ ferromagnetic interaction due to the increase in antisite disorder, which is considered as a triggering factor of the negative magnetization. Therefore, the observed effect is regarded as arising from the negative exchange coupling between $\mathrm{G}{\mathrm{d}}^{3+}$ and $\mathrm{N}{\mathrm{i}}^{2+}/\mathrm{M}{\mathrm{n}}^{4+}$ local sublattice moments, which have different temperature dependence according to the Néel molecular field theory.

We embrace a high-throughput investigation strategy beginning from the electronic structure properties to examine three vanadium-based half Heusler alloys with 18 valence electrons, $\mathrm{VRh}Z$ $(Z=\mathrm{Ge},\mathrm{Si}, \text{and} \mathrm{Sn})$, for thermoelectric application. This work is inspired by expected contrasting electrical transport essentials, particularly high electrical conductivity $\sigma$ and high Seebeck coefficient $S$ for attaining enhanced figure of merit $\left(ZT\right)$ performance. We employ the electronic fitness function $\left(\text{EFF}\right)$, which evaluates the magnitude of decoupling $\sigma$ and $S$ for high $ZT$ by a distinct band structure. The impact of varying the Fermi level on the power factor, electrical conductivity, and Seebeck coefficient is explored. The effects of exchange correlation are reported by use of the Perdew-Burke-Ernzerhof (PBE) functional in line with the framework of the generalized gradient approximation (GGA), as implemented in the ab initio density functional theory. To rigorously assess the reliability of the GGA-PBE functional, subsequent electronic structure calculations are carried out on the three compounds using the $\mathit{GW}$ approximation. We obtain lattice constants of $a_0=5.79\AA ,a_0=5.76\AA$, and $a_0=6.09\AA$ for VRhGe, VRhSi, and VRhSn, respectively. All materials exhibit ductility as indicated by their values of Cauchy pressure, as well as Poisson's ratio and Pugh's ratio values. The VRhSn machinability index is the highest at 2.2456. The highest hardness is realized in VRhSi, which is at 7.9957 GPa. Based on the Kleinman parameter, bond stretching is negligible in all $\mathrm{VRh}Z$ materials. $\mathrm{VRh}Z$ spatial dependence plots indicate that all investigated compounds are anisotropic. In this study, dynamic stability is observed in all compounds due to the nonexistence of phonon modes that correspond to imaginary frequencies. The derived electronic energy band structure reveals that all three alloys exhibit semiconductor properties with band gap energies of 0.50, 0.32, and 0.42 eV in VRhGe, VRhSi, and VRhSn, respectively, corresponding to indirect transitions. The maximum values realized for the EFF when $T=1000\text{K}$ using $\mathit{GW}$ are $0.69\times {10}^{-19}{W}^{\frac{5}{3}}\text{m}{\text{s}}^{\frac{-1}{3}}{\text{K}}^{-2}, 0.66\times {10}^{-19}{W}^{\frac{5}{3}}\text{m}{\text{s}}^{\frac{-1}{3}}{\text{K}}^{-2}, 0.79\times {10}^{-19}{W}^{\frac{5}{3}}\text{m}{\text{s}}^{\frac{-1}{3}}{\text{K}}^{-2}$ for VRhGe, VRhSi, and VRhSn, respectively. The observed $ZT$ values at 1000 K using $\mathit{GW}$ are 0.91, 0.99, and 0.99 for VRhGe, VRhSi, and VRhSn, respectively. These results of $ZT$ as well as EFF suggest that $\mathrm{VRh}Z$ ($Z=\mathrm{Ge}$, Si, and Sn) compounds are promising high-temperature thermoelectric materials.

Reinforcement fine-tuning played an instrumental role in enhancing the instruction-following and reasoning abilities of large language models. In this work, we employ reinforcement fine-tuning for materials design, in which discriminative machine learning models are used to provide rewards to the autoregressive transformer-based materials generative model CrystalFormer [Sci. Bull. 70, 3522 (2025)]. By optimizing the reward signals—such as energy above the convex hull and material property figures of merit—reinforcement fine-tuning infuses knowledge from discriminative models into generative models. The resulting model, CrystalFormer-RL, shows enhanced stability in generated crystals and successfully discovers crystals with desirable yet conflicting material properties, such as substantial dielectric constant and band gap simultaneously. Notably, we observe that reinforcement fine-tuning not only enables the property-guided material design but also unlocks property-based material retrieval behavior of pretrained generative model. The present framework opens an exciting gateway to the synergies of the machine learning ecosystem for materials design.

Landau-Zener tunneling (LZT) is a fundamental dynamical phenomenon, ubiquitous in various quantum systems. Here, we propose a time-varying electric circuit to address the question of whether the quantum LZT can occur in classical systems. Although the underlying differential equation of motion is quite different from the Schrödinger equation and the instantaneous frequency spectrum of the proposed circuit is not linear, the probability of the LZT in circuits (circuit LZT for short), based on our generalized definition for norm-unconserved systems, still follows the laws of the LZT in quantum systems, codetermined by the linear sweeping rate ${\alpha }^{\prime }$ and the frequency gap $\mathrm{\Delta }$, i.e., approaching the analytical value $exp(-\pi {\mathrm{\Delta }}^2/2{\alpha }^{\prime })$, regardless of whether the coupling is reciprocal or nonreciprocal. The deep relationship between the circuit LZT and its quantum counterpart can be established through a linearization and block-diagonalization process. Our proposal provides a general method for simulating time-dependent quantum models using time-varying electric circuits, which has been lacking in previous studies, and paves the way for studying more complicated LZT and other dynamical phenomena in circuits and other classical systems.

In this work, we investigate chiral topological superconductors on a two-dimensional honeycomb lattice with coexisting $d_{x^2-y^2}, d_{xy}$, and $s$-wave pairing symmetries. Using a Ginzburg-Landau free energy analysis, the pairing gap function is shown to exhibit a tri-component form $s+d_{x^2-y^2}{e}^{i{\varphi }_1}+d_{xy}{e}^{i{\varphi }_2}$, where ${\varphi }_1$ and ${\varphi }_2$ are phase differences between the $d$- and $s$-wave pairing components, which spontaneously breaks both time reversal and $C_6$ rotational symmetries. Chern numbers of the energy bands are calculated to be nonzero, demonstrating the topologically nontrivial nature of the system. The anomalous AC Hall conductivity is computed, which is not invariant under $C_6$ rotations, reflecting the anisotropic nature of the pairing gap function. Fractional magnetic vortices are also discussed, arising from the multicomponent nature of the pairing gap function.

Trilayer Ruddlesden-Popper nickelate superconductor ${\mathrm{La}}_4{\mathrm{Ni}}_3{\mathrm{O}}_{10}$ has generated considerable interest due to its unconventional superconductivity and complex electronic structure. Notably, ${\mathrm{La}}_4{\mathrm{Ni}}_3{\mathrm{O}}_{10}$ features a mixed Ni valence state and an asymmetric trilayer configuration, leading to distinct quasiparticle distributions and local density of states (LDOS) between the inner and outer ${\mathrm{NiO}}_2$ planes. In this work, we investigate impurity-induced states in ${\mathrm{La}}_4{\mathrm{Ni}}_3{\mathrm{O}}_{10}$ using a two-orbital model combined with $T$-matrix formalism, focusing on the contrasting roles of intra- and interlayer pairing channels. Our self-consistent mean-field analysis reveals that interlayer pairing results in partially gapless Fermi surfaces, with unpaired quasiparticles concentrated in the outer layers and a pronounced low-energy LDOS. We demonstrate that impurity effects vary significantly depending on both the pairing symmetry and impurity location: interlayer-dominant pairing produces sharp resonance states when impurities are in the inner layer, whereas impurities in the outer layer lead to in-gap enhancements without sharp resonances; in contrast, intralayer-dominant pairing generally yields increased in-gap LDOS without sharp impurity resonances, regardless of impurity position. These findings suggest that single-impurity spectroscopy can serve as a powerful probe to distinguish between competing superconducting pairing mechanisms in trilayer nickelates and highlight the rich physics arising from their multilayer structure.

Searching for materials with substantial magnetoresistance (MR) serves as an interesting academic challenge while holding central significance for modern technological applications in magnetic data storage and spintronics. Here, we systematically investigate the Shubnikov-de Haas (SdH) quantum oscillations and magnetotransport properties in high-quality single crystals of quasi-one-dimensional (quasi-1D) topological semimetal ${\mathrm{Ta}}_2{\mathrm{PdSe}}_6$, which is a quasi-1D layered ternary transition metal trichalcogenide with a chain-like structure along the $b$ axis. The nonsaturating XMR of $3.6\times {10}^4\%$ along the intrachain direction and $1.6\times {10}^4\%$ along the interchain direction at 35 T and 1.7 K in ${\mathrm{Ta}}_2{\mathrm{PdSe}}_6$ was observed. Additionally, the $x\text{−}z$ AMR curves change from a dumbbell-like pattern with $A_2$ symmetry to an irregular butterfly-like pattern with $A_n$ ($n>2$) as the temperature drops below $T^{*}=20\mathrm{K}$. The analyses of the measured $y\text{−}z$ AMR results reveal that the higher-order symmetry components $A_4$ and $A_6$ are maximized around $T^{*}$. Hall effect measurements reveal that the carrier concentrations deviate from the 1:1 ratio at low temperatures with transport dominated by hole carriers, while the carrier concentrations exhibit an abrupt change and carrier mobilities increase around $T^{*}$ in ${\mathrm{Ta}}_2{\mathrm{PdSe}}_6$. Based on the findings, we conclude that the emergence of higher-order symmetry in the AMR at low temperatures may be associated with the modulation of the density of states near the Fermi level or the dominance of high-mobility carriers in transport. Our study further advances the understanding of uncommon magnetotransport properties in quasi-1D topological semimetals and establishes experimental support for the potential application of anisotropic spintronic devices.

The recently discovered kagome superconductor ${\mathrm{CsV}}_3{\mathrm{Sb}}_5$ exhibits a rich interplay between superconductivity (SC) and charge density wave order, both of which are highly tunable via doping or pressure. In particular, hole doping ${\mathrm{CsV}}_3{\mathrm{Sb}}_5$ by substituting vanadium with the relatively smaller titanium allows controlled tuning of the correlated phases, revealing two distinct superconducting domes (SC I and SC II) across the doping range. A prior tunneling experiment [H. Yang, et al., Sci. Bull. 67, 2176 (2022)] suggests differing SC pairing symmetries between the two domes. Since the Fermi surface topology—including features such as pockets, nesting vectors, and dimensionality—plays a crucial role in determining the superconducting pairing mechanism, we investigate its evolution in ${\mathrm{CsTi}}_x{\mathrm{V}}_{3-x}{\mathrm{Sb}}_5$ across four doping levels ($x=0$, 0.03, 0.10, and 0.15), spanning both SC domes. High-field torque magnetometry up to 41 T reveals pronounced de Haas–van Alphen (dHvA) oscillations, with distinct frequency spectra observed in SC I and SC II, implying that these SC domes have different electronic and Fermi surface properties. First-principles calculations using density functional theory also show changes in key electronic features—such as Dirac crossings, van Hove singularities, and flat bands—when vanadium is replaced with titanium. Notably, the Fermi surface topology shows clear deformation with increasing titanium doping. Our experimental and theoretical results provide compelling evidence for distinct Fermi surface characteristics in the SC I and SC II regions, offering insights into the possible existence of different pairing mechanisms across the two superconducting domes in ${\mathrm{CsTi}}_x{\mathrm{V}}_{3-x}{\mathrm{Sb}}_5$.

This study addresses the theoretical challenges in near-field thermal radiation regulation of time-varying media by proposing an extended framework of fluctuational electrodynamics based on the Fourier modal method. Through temporal Fourier decomposition of permittivity and scattering matrix chain operations, we construct an operator-based model suitable for high-frequency modulated systems, systematically resolving the nonreciprocal regulation mechanism of near-field thermal radiation under temporal modulation. Our analysis demonstrates that temporal modulation induces frequency conversion of surface polaritons, effectively creating multiple photon transport channels via sideband generation. The introduction of a phase difference between modulation layers breaks the time-reversal symmetry of photon propagation paths, leading to nonreciprocal heat transfer. Furthermore, by designing a multilayer structure that enhances the coupling between temporal and spatial modulation, we achieve a near-field thermal rectification coefficient of 0.5. The proposed theoretical framework provides a semi-analytical tool for investigating modal interactions in infrared time-varying media, opening avenues for nonmagnetic, actively controllable thermal management devices.

More physics at the boundaries of a topological lattice remains to be explored for future applications of topological edge states. This work investigates the stability of topological edge states in the presence of a moving impurity. By modeling the impurity as a moving Gaussian on-site potential at the boundary of a two-dimensional lattice, we show that a moving impurity may cause significant modifications to edge transport, a feature markedly different from the expected robustness of edge transport against a static impurity. We further identify an interesting mechanism to explain the bulk-edge coupling using a comoving frame, where the density of the bulk states and the degeneracy between the edge states and the bulk become key elements. The physical insights developed in this work are validated across multiple systems, including Chern insulators, quantum spin Hall insulators, and Floquet-Chern insulators. The results presented in this work are complementary to our current understanding of the robustness of topological edge transport.

The recently discovered cobalt oxychalcogenide superconductor ${\mathrm{Na}}_2{\mathrm{CoSe}}_2\mathrm{O}$ has attracted great attention due to its interesting properties, such as superconductivity, quasi-two-dimensionality, low carrier concentration, and very high upper critical field [J. Cheng et al., J. Am. Chem. Soc. 146, 5908 (2024)]. Nevertheless, the underlying superconducting mechanism of ${\mathrm{Na}}_2{\mathrm{CoSe}}_2\mathrm{O}$ remains unclear and needs further theoretical clarification. In this work, we have systematically investigated the electronic structures, lattice dynamics, and superconducting properties of ${\mathrm{Na}}_2{\mathrm{CoSe}}_2\mathrm{O}$ by performing first-principles calculations. Our computational results suggest that the superconductivity in ${\mathrm{Na}}_2{\mathrm{CoSe}}_2\mathrm{O}$ originates from the strong electron-phonon coupling rather than the electronic correlation of Co $3d$ electrons. The calculated superconducting transition temperature $T_{\text{c}}$ of 5.7 K agrees quite well with the experimental value, indicating that the superconducting pairing in ${\mathrm{Na}}_2{\mathrm{CoSe}}_2\mathrm{O}$ belongs to the conventional Bardeen-Cooper-Schrieffer (BCS) type. Additionally, we find that the spin-orbital coupling (SOC) effect can induce unique spin textures for the bands around the Fermi level, which may explain the experimentally observed high upper critical field and its anisotropy along the in-plane and out-of-plane directions. Inspired by the results of ${\mathrm{Na}}_2{\mathrm{CoSe}}_2\mathrm{O}$, we also predict the ${\mathrm{CoSe}}_2/{\mathrm{Ca}}_2\mathrm{N}$ bilayer heterostructure as a two-dimensional (2D) superconductor with the superconducting $T_{\text{c}}$ of 5.1 K. Our identification on the nature of superconductivity in ${\mathrm{Na}}_2{\mathrm{CoSe}}_2\mathrm{O}$ and prediction on the ${\mathrm{CoSe}}_2/{\mathrm{Ca}}_2\mathrm{N}$ superconductor call for future experimental verifications.