arXiv subjects

Zhigao Huang

Publications and source records attributed to Zhigao Huang.

15 recordsLinked to original sources

arXiv2026

IFPV: An Integrated Multi-Agent Framework for Generative Operational Planning and High-Fidelity Plan Verification

Operational plan generation and verification are critical for modern complex and rapidly changing battlefield environments, yet traditional generation and verification methods still respectively face the challenges of generation infeasibility and verification insufficiency. To alleviate these limitations, we propose an Integrated Multi-Agent Framework for Generative Operational Planning and High-Fidelity Plan Verification (IFPV). IFPV consists of two tightly coupled modules: Multi-Perspective Hierarchical Agents (MPHA) for generative operational planning and an Adversarial Cognitive Simulation Engine (ACSE) for high-fidelity adversarial plan verification. MPHA decomposes commander intent into executable multi-platform tactical action sequences through the collaboration of Pathfinder, Analyst, and Planner agents. ACSE introduces an opponent equipped with a customized world model, which predicts the future evolution of mission-critical platforms and conducts dynamic counteractions against candidate plans. Simulation experiments in the Asymmetric Combat Tactic Simulator (ACTS) show that IFPV improves mission success by 19.4% and reduces operational cost by 41.7% compared with a single-step large language model (LLM) planning baseline. Compared with a traditional rule-based validator, ACSE increases the average suppression rate by 31.8%, indicating that the proposed verification environment is stricter and more discriminative in revealing the latent vulnerabilities of candidate plans. The code for IFPV can be found at https://github.com/zhigao3ks/IFPV.

cs.MA↗

arXiv2025

Spin-Selective Second-Order Topological Insulators Enabling Cornertronics in 2D Altermagnets

Recent progress in spintronics within the paradigm of altermagnets (AMs) opens new avenues for next-generation electronic device design. Here, we establish a spin-corner locking mechanism that generates second-order topological states in two-dimensional (2D) altermagnetic systems, through effective model analysis. Remarkably, the breaking of Mxy symmetry under uniaxial strain creates spin-resolved corner modes, driving the system into a corner-polarized second-order topological insulator (CPSOTI). Beyond critical strain, a topological phase transition to quantum anomalous Hall insulator occurs with quantized conductance. Through first-principles calculations, we identify two experimentally viable candidates for 2D intrinsic AM CrO and Cr$_2$Se$_2$O -- which host robust CPSOTI. Moreover, we construct the topological phase diagram of CrO and predict the existence of an altermagnetic Weyl semimetal phase. Our findings open technological avenues in altermagnetism and higher-order topology, while providing opportunities for coupling topological spintronics with cornertronics.

cond-mat.mes-hall↗

arXiv2025

Sliding Ferroelectrics Induced Hybrid-Order Topological Phase Transitions

We propose ferroelectric layer sliding as a new approach to realize and manipulate topological quantum states in two-dimensional (2D) bilayer magnetic van der Waals materials. We show that stacking monolayer ferromagnetic topological states into layer-spin-locked bilayer antiferromagnetic structures, and introducing sliding ferroelectricity leads to asynchronous topological evolution of different layers (spins) owing to existence of polarization potentials, thereby giving rise to rich layer-resolved topological phases. As a specific example, by means of a lattice model, we show that a bilayer magnetic 2D second order topological insulator (SOTI) reveals an unrecognized spin-hybrid-order topological insulator after undergoing ferroelectric sliding. Interestingly, in such phase, the spin-up (top layer) and spin-down (bottom layer) channels exhibit first-order and second-order topological properties, respectively. Moreover, other topological phases such as SOTI, quantum spin Hall insulator, quantum anomalous Hall insulator, and trivial insulator can also emerge through changes in the parameters of the system, and the relevant topological indices are also discussed. In terms of materials, based on first principles calculations, we predict material ScI2 can serve as an ideal platform to realize our proposal. Further, we predict that the anomalous Nernst effect of these several topological phases exhibits distinct differences, and therefore can be used as a signal for experimentally probing.

cond-mat.mtrl-sci↗

arXiv2025

Topological electron and phonon flat bands in novel kagome superconductor XPd5 (X=Ca, Sr, Ba)

Fermionic and bosonic localized states induced by geometric frustration in the kagome lattice provide a distinctive research platform for investigating emergent exotic quantum phenomena in strongly correlated systems. Here, we report the discovery of coexisting electronic and phononic flat bands induced by geometric frustration in a novel kagome superconductor XPd5 (X=Ca, Sr, Ba). The electronic flat band is located around the Fermi level and possesses a nontrivial topological invariant with Z2=1. Additionaly, we identify multiple van Hove singularities (vHS) arise from the kagome Pd d orbitals with distinct dispersion and sublattice features, including conventional, higher-order vHS and p-type, m-type vHS. Specifically, our investigation of the vibrational modes of the phononic flat band reveals that its formation originates from destructive interference between adjacent kagome lattice sites with antiphase vibrational modes. A spring-mass model of phonons is established to probe the physical mechanism of the phononic flat bands. Furthermore, the calculations of electron-phonon coupling in the XPd5 reveal superconducting ground states with critical temperatures (Tc) of 4.25 K, 2.75 K, and 3.35 K for CaPd5, SrPd5, and BaPd5, respectively. This work provides a promising platform to explore the Fermion-boson many-body interplay and superconducting states, while simultaneously establishing a novel analytical framework to elucidate the origin of phononic flat bands in quantum materials.

cond-mat.supr-con↗

arXiv2024

Hybrid-Order Topological Phase And Transition in 1H Transition Metal Compounds

Inspired by recent experimental observations of hybrid topological states [Hossain et al. Nature 628, 527 (2024)], we predict hybrid-order topological insulators in 1H transition metal compounds (TMCs), where both second-order and first-order topological (FOT) states coexist near the Fermi level. Initially, 1H-TMCs exhibit a second-order topological phase due to the d orbital bandgap. Upon coupling of p and d orbitals through the crystal field effect, first-order topological characteristics emerge. This hybrid-order topological phase transition can be tuned via crystal field effects. Combined with first-principles calculations, we illustrate the phase transition with WTe2 and NbSe2. The WTe2 exhibits hybrid-order under ambient conditions, while NbSe2 transitions to hybrid-order under pressure. Additionally, the first-order topological bandgap in the HyOTI demonstrates a strong spin Hall effect. Our findings reveal a hybrid-order topological phase in two-dimensional electron materials and underscore spintronic applications.

cond-mat.mtrl-sci↗

arXiv2024

Novel magnetic topological insulator FeBi$_2$Te$_4$ with controllable topological quantum phase

Here, we report a new intrinsic magnetic topological insulator FeBi$_2$Te$_4$ based on first-principles calculations and it can achieve a rich topological phase under pressure modulation. Without pressure, we predict that both FeBi$_2$Te$_4$ ferromagnetic and antiferromagnetic orders are non-trivial topological insulators. Furthermore, FeBi$_2$Te$_4$ of FM-z order will undergo a series of phase transitions from topological insulator to semimetals and then to trivial insulator under pressure. Finally, we further clarify and verify topological phase transitions with low-energy effective model calculations. This topological phase transition process is attributed to the synergy of the magnetic moment and the spin-orbit coupling. The unique topological properties of FeBi$_2$Te$_4$ will be of great interest in driving the development of quantum effects.

cond-mat.mes-hall↗

arXiv2024

Thermal and mechanical properties and the structural phase transition under pressure in $A$In$_2$As$_2$ ($A$ = Ca, Sr, Ba)

Experimental results that BaIn2As2 and Ca(Sr)In2As2, which are the same class of alkali metal compounds, belong to different structural phases have puzzled the current materials physics community. Here, we investigate the pressure-induced structural phase transition of AIn2As2 and its accompanying improvement in mechanical and thermal properties. Firstly, the structural stability of the materials and their structural phase transitions under pressure are characterized by enthalpy and double checking by phonon dispersion spectrum. We also confirm the structural phase transitions of the hexagonal and monoclinic phases from a group-theoretic point of view, associating their symmetry operations using transformation matrices. In terms of mechanical properties, we propose an effective scheme for pressure modulation of the anisotropy of AIn2As2 materials and to induce the transformation of AIn2As2 from isotropic to anisotropic (hexagonal) and from brittle to ductile (hexagonal and monoclinic). Meanwhile, we find the negative Poisson's ratio phenomenon under compression and tension, which is favorable for a wide range of applications of this series of materials in aerospace, medicine, sensors, etc. In terms of thermal properties, applying pressure will enhance the structural phase transition temperature of AIn2As2 materials to near room temperature. We further give direct evidence of phonon softening based on group velocity calculations and reveal that phonon softening prevents the heat capacity from reaching the Dulong-Petit limit. Our study provides a theoretical basis for selecting stable structural phases and pioneering thermodynamic property studies of the thermoelectric topological candidate material AIn2As2.

cond-mat.mtrl-sci↗

arXiv2023

Topological Phases, Local Magnetic Moments, and Spin Polarization Triggered by C558-Line Defects in Graphene

We study the electronic properties of a novel topological defect structure for graphene interspersed with C558-line defects along the Armchair boundary. This system has the topological property of being topologically three-periodic and the type-II Dirac-fermionic character of the embedded topological phase. At the same time, we show computationally that the topological properties of the system are overly dependent on the coupling of this line defect. Using strain engineering to regulate the magnitude of hopping at the defect, the position of the energy level can be easily changed to achieve a topological phase transition. We also discuss the local magnetic moment and the ferromagnetic ground state in the context of line defects, which is the conclusion after considering additional Coulomb interactions. This leads to spin polarization of the whole system. Finally, by modulating the local magnetic moment at the position of the line defect, we achieve a tunable spin quantum conductance in a one-dimensional nanoribbon. Near the Fermi energy level, it also has the property of complete spin polarization. Consequently, spin filtering can be achieved by varying the incident energy of the electrons.

cond-mat.mes-hall↗

arXiv2021

The evolution of Weyl nodes in Ni doped thallium niobate pyrochlore Tl$_{2-x}$Ni$_x$Nb$_2$O$_7$

Magnetic Weyl semimetal (WSM) is of great importance both for fundamental physics and potential applications due to its spontaneous magnetism, robust band topology, and enhanced Berry curvature. It possesses many unique quantum effects, including large intrinsic anomalous Hall effect, Fermi arcs, and chiral anomaly. In this work, using ab initio calculations, we propose that Ni doped pyrochlore Tl$_2$Nb$_2$O$_7$ is a magnetic WSM caused by exchange field splitting on bands around its quadratic band crossing point. The exchange field tuned by Ni 3d on-site Coulomb interaction parameter $U$ drives the evolution of Weyl nodes and the resulting topological phase transition. Since Weyl nodes can exist at generic point in Brillouin zone and are hard to be exactly identified, the creation and annihilation of them, i.e., the change in their number, chirality and distribution, have been consistently confirmed with a combined theoretical approach, which employs parity criterion, symmetry indicator analysis and the Wilson loop of Wannier center. We find that Weyl nodes remain in a quite large range of $U$ and are close to Fermi level, which makes the experimental observation very possible. We think this method and our proposal of magnetic WSM will be useful in finding more WSMs and adding our understanding on the topological phase transition.

cond-mat.mtrl-sci↗

arXiv2021

Topological quantum phase transition in the magnetic semimetal HoSb

Magnetic topological semimetals, a novel state of quantum matter with nontrivial band topology, have emerged as a new frontier in physics and materials science. An external stimulus like temperature or magnetic field could be expected to alter their spin states and thus the Fermi surface anisotropies and topological features. Here, we perform the angular magnetoresistance measurements and electronic band structure calculations to reveal the evolution of HoSb's Fermi surface anisotropies and topological nature in different magnetic states. The angular magnetoresistance results manifest that its Fermi surface anisotropy is robust in the paramagnetic state but is significantly modulated in the antiferromagnetic and ferromagnetic states. More interestingly, a transition from the trivial (nontrivial) to nontrivial (trivial) topological electronic phase is observed when HoSb undergoes a magnetic transition from the paramagnetic (antiferromagnetic) to antiferromagnetic (ferromagnetic) state induced by temperature (applied magnetic field). Our studying suggests that HoSb provides an archetype platform to study the correlations between magnetism and topological states of matter.

cond-mat.mtrl-sci↗

arXiv2019

Adsorption and ultrafast diffusion of lithium in bilayer graphene ab initio and kinetic Monte Carlo simulation study

In this work, we adopt first-principle calculations based on density functional theory and Kinetic Monte Carlo simulations to investigate the adsorption and diffusion of lithium in bilayer graphene (BLG) as anodes in lithium-ion batteries. Based on energy barriers directly obtained from first-principle calculations for single-Li and two-Li intercalated BLG, a new equation was deduced for predicting energy barriers considering Li's interactions for multi-Li intercalated BLG. Our calculated results indicate that Li energetically prefers to intercalate within rather than adsorb outside the bilayer graphene. Additionally, lithium exists in cationic state in the bilayer graphene. More excitingly, ultrafast Li diffusion coefficient, within AB-stacked BLG near room temperature was obtained, which reproduces the ultrafast Li diffusion coefficient measured in recent experiment. However, ultrafast Li diffusion was not found within AA-stacked BLG near room temperature. The analyses of potential distribution indicate that the stacking structure of BLG greatly affects its height of potential well within BLG, which directly leads to the large difference in Li diffusion. Furthermore, it is found that both the interaction among Li ions and the stacking, structure cause Li diffusion within AB-stacked BLG to exhibit directional preference. Finally, the temperature dependence of Li diffusion is described by the Arrhenius law. These findings suggest that the stacking structure of BLG has an important influence on Li diffusion within BLG, and changing the stacking structure of BLG is one possible way to greatly improve Li diffusion rate within BLG. At last, it is suggested that AB-stacked BLG can be an excellent candidate for anode material in Lithium-ion batteries.

cond-mat.mes-hall↗

arXiv2015

Electronic and Transport Property of Phosphorene Nanoribbon

By combining density functional theory and nonequilibrium Green's function, we study the electronic and transport properties of monolayer black phosphorus nanoribbons (PNRs). First, we investigate the band-gap of PNRs and its modulation by the ribbon width and an external transverse electric feld. Our calculations indicate a giant Stark effect in PNRs, which can switch on transport channels of semiconducting PNRs under low bias, inducing an insulator-metal-transition. Next, we study the transport channels in PNRs via the calculations of the current density and local electron transmission pathway. In contrast to graphene and MoS_2 nanoribbons, the carrier transport channels under low bias are mainly located in the interior of both armchair and zigzag PNRs, and immune to a small amount of edge defects. Lastly, a device of the PNR-based dual-gate feld-effect-transistor, with high on/off-ratio of 10^3, is proposed based on the giant electric feld tuning effect.

cond-mat.mes-hall↗

arXiv2014

Efficient spin injection into graphene through a tunnel barrier: overcoming the spin conductance mismatch

Employing first-principles calculations, we investigate efficiency of spin injection from a ferromagnetic (FM) electrode (Ni) into graphene and possible enhancement by using a barrier between the electrode and graphene. Three types of barriers, h-BN, Cu(111), and graphite, of various thickness (0-3 layers) are considered and the electrically biased conductance of the Ni/Barrier/Graphene junction are calculated. It is found that the minority spin transport channel of graphene can be strongly suppressed by the insulating h-BN barrier, resulting in a high spin injection efficiency. On the other hand, the calculated spin injection efficiencies of Ni/Cu/Graphene and Ni/Graphite/Graphene junctions are low, due to the spin conductance mismatch. Further examination on the electronic structure of the system reveals that the high spin injection efficiency in the presence of a tunnel barrier is due to its asymmetric effects on the two spin states of graphene.

cond-mat.mtrl-sci↗

arXiv2013

Stability, Electronic and Magnetic properties of magnetically doped topological insulators Bi2Se3, Bi2Te3 and Sb2Te3

Magnetic interaction with the gapless surface states in topological insulator (TI) has been predicted to give rise to a few exotic quantum phenomena. However, the effective magnetic doping of TI is still challenging in experiment. Using first-principles calculations, the magnetic doping properties (V, Cr, Mn and Fe) in three strong TIs (Bi$_{2}$Se$_{3}$, Bi$_{2}$Te$_{3}$ and Sb$_{2}$Te$_{3}$) are investigated. We find that for all three TIs the cation-site substitutional doping is most energetically favorable with anion-rich environment as the optimal growth condition. Further our results show that under the nominal doping concentration of 4%, Cr and Fe doped Bi$_{2}$Se$_{3}$, Bi$_{2}$Te$_{3}$, and Cr doped Sb$_{2}$Te$_{3}$ remain as insulator, while all TIs doped with V, Mn and Fe doped Sb$_{2}$Te$_{3}$ become metal. We also show that the magnetic interaction of Cr doped Bi$_{2}$Se$_{3}$ tends to be ferromagnetic, while Fe doped Bi$_{2}$Se$_{3}$ is likely to be antiferromagnetic. Finally, we estimate the magnetic coupling and the Curie temperature for the promising ferromagnetic insulator (Cr doped Bi$_{2}$Se$_{3}$) by Monte Carlo simulation. These findings may provide important guidance for the magnetism incorporation in TIs experimentally.

cond-mat.mtrl-sci↗

arXiv2012

A molecular dynamics investigation of the mechanical properties of graphene nanochain

In this paper, we investigate, by molecular dynamics simulations, the mechanical properties of a new carbon nanostructure, termed graphene nanochain, constructed by sewing up pristine or twisted graphene nanoribbons (GNRs) and interlocking the obtained nanorings. The obtained tensile strength of defect-free nanochain is a little lower than that of pristine GNRs and the fracture point is earlier than that of the GNRs. The effects of length, width and twist angle of the constituent GNRs on the mechanical performance are analyzed. Furthermore, defect effect is investigated and in some high defect coverage cases, an interesting mechanical strengthening-like behavior is observed. This structure supports the concept of long-cable manufacturing and advanced material design can be achieved by integration of nanochain with other nanocomposites. The technology used to construct the nanochain is experimentally feasible, inspired by the recent demonstrations of atomically precise fabrications of GNRs with complex structures [Phys. Rev. Lett,2009,\textbf{102},205501; Nano Lett., 2010, \textbf{10},4328; Nature,2010,\textbf{466},470]

cond-mat.mtrl-sci↗