arXiv subjects

Xueqing Wan

Publications and source records attributed to Xueqing Wan.

4 recordsLinked to original sources

arXiv2026

Light-Driven Ferroic Switching Enables Reversible Control of Hydrogen Adsorption Thermodynamics

Reversible ultrafast switching of surface thermodynamics is highly desirable for hydrogen storage and catalysis yet remains elusive at the nanoscale. Here we demonstrate that photoinduced ferroic-order switching in two-dimensional ionic ferroelectric monolayers enables rapid, reversible control of hydrogen binding. In TiGeSe$_3$, carrier-density-driven redistribution of transition-metal 3\textit{d} orbital occupations triggers a sequential evolution from the ferroelectric ground state to paraelectric phases with staggered or Zig-Zag antiferromagnetic order. This switch continuously tunes the hydrogen adsorption free energy from 0.33 to 1.11 eV, shifting the interface from near-thermoneutrality to spontaneous desorption. Nonadiabatic dynamics indicate that electron-phonon coupling promotes nonthermal H release, while picosecond carrier recombination rapidly restores the initial ferroic order, closing an ultrafast reversible cycle. Generality is further validated in AgBiP$_2$Se$_6$ and CuInP$_2$S$_6$, establishing ferroic order as an optically addressable knob for dynamic thermodynamic reconfiguration beyond static design.

cond-mat.mtrl-sci↗

arXiv2025

Ferroelectric Switchable Topological Magnon Hall Effect in Type-I Multiferroics

Electric control of magnetism at room temperature is crucial for developing next-generation, low-power spintronic devices. However, the intrinsic incompatibility between ferroelectricity and magnetism in crystal symmetry, along with the absence of strong magnetoelectric coupling mechanisms, continues to pose major challenges. In this work, we propose a general theoretical framework for magnon manipulation based on ferroelectric polarization switching in two-dimensional multiferroics. Taking monolayer multiferroics $\mbox{Ti}_{2}\mbox{F}_{3}$ as an example, our calculations demonstrate that ferroelectric switching can significantly modulate spin exchanges, thereby enabling nonvolatile and reversible electric control of the magnons. More importantly, the ferroelectric polarization reversal leads to a sign change in the Berry curvature, ensuring effective control over the valley Hall and nonlinear Hall response of magnons. This study provides a new way for realizing low-power and electrically controllable magnonic devices.

cond-mat.mtrl-sci↗

arXiv2025

Electro-optic effects in some sliding ferroelectrics

Sliding ferroelectrics, which exhibit out-of-plane polarization arising from specific stacking rather than conventional ionic displacements, are new types of ferroelectrics whose underdeveloped physics needs to be explored. Here, we investigate the electro-optic (EO) response of these materials using first-principles calculations, focusing on ZrI$_{2}$ as a prototype. We reveal that, contrary to conventional ferroelectrics, the EO effect in ZrI$_{2}$ is dominated by its electronic contribution rather than the ionic one, which promises faster EO responses. Furthermore, both biaxial and uniaxial strains significantly enhance this response, and a universal-like linear relationship between the band gap and such response is discovered. We also report a large elasto-optic coefficient that is independent of biaxial strain. Similar large linear EO coefficients and properties are found in other sliding ferroelectrics, including different zirconium dihalides, as well as BN and BP bilayers. These findings highlight sliding ferroelectrics as highly promising candidates for ultrafast nonlinear optical devices and reveal unusual mechanisms.

cond-mat.mtrl-sci↗

arXiv2025

Topological switching in bilayer magnons via electrical control

Topological magnons, quantized spin waves featuring nontrivial boundary modes, present a promising route toward lossless information processing. Realizing practical devices typically requires magnons excited in a controlled manner to enable precise manipulation of their topological phases and transport behaviors. However, their inherent charge neutrality and a high frequency nature pose a significant challenge for nonvolatile control, especially via electric means. Herein, we propose a general strategy for electrical control of topological magnons in bilayer ferromagnetic insulators. With strong spin-layer coupling, an applied vertical electric field induces an interlayer potential imbalance that modifies intralayer Heisenberg exchanges between adjacent layers. This electric-field-driven modulation competes with the bilayer's intrinsic Dzyaloshinskii-Moriya interaction, enabling the accurate tuning of the band topology and nonreciprocal dynamics of magnons. More importantly, such an electric control mechanism exhibits strong coupling with external magnetic fields, unveiling new perspectives on magnetoelectric coupling in charge-neutral quasiparticles

cond-mat.mes-hall↗