arXiv subjects

Guibo Zheng

Publications and source records attributed to Guibo Zheng.

3 recordsLinked to original sources

arXiv2026

Nonvolatile Control of Nonlinear Hall and Circular Photogalvanic Effects via Berry Curvature Dipole in Multiferroic Monolayer CrNBr2

The Berry curvature dipole induced by symmetry breaking play a pivotal role in electronic transport properties and nonlinear responses, such as the nonlinear Hall effect and circular photogalvanic effect. The study of the Berry curvature dipole, often explored in time-reversal symmetric systems, but it should not be limited to such materials. Here, we predicted that the ferroelectricity in monolayer CrNBr2 produces Berry curvature dipole, leading to the nonlinear Hall effect and circular photogalvanic current. The linear anomalous Hall effect and circularly polarized optical absorption, governed by spin-orbit coupling, are independent of ferroelectric polarization and exhibit extremely small conductance. In contrast, multiferroic monolayer CrNBr2 achieves a large nonlinear Hall conductivity and circular photogalvanic current, despite its suppression at high temperatures from phonon scattering. The coupling between the ferroelectric polarization and the Berry curvature dipoles allows for nonvolatile switching of these effects, presenting substantial promise for nanoelectronic and optoelectronic devices.

cond-mat.mtrl-sci↗

arXiv2025

Spin-chirality-dependent modulation of topological gap, Chern number, and valley-polarization in monolayer kagome lattice Cr3Se4

Kagome materials exhibit unique electronic properties, such as the quantum anomalous Hall effect. The control of Chern numbers is critical for quantum device manipulation, but existing research has mainly focused on collinear magnetization while neglecting chiral spin textures. Through first-principles calculations and tight-binding modeling of monolayer Cr3Se4, this study reveals spin-chirality-dependent control of topological gaps, Chern numbers, and valley polarization in kagome materials. The results demonstrate that the azimuthal angle has no observable effect. For collinear magnetization (\k{appa} = 0) or spin-chirality \k{appa} = -1, the topological bandgap decreases as the spin orientation approaches the in-plane direction. Conversely, increasing the polar angle enhances the bandgap for \k{appa} = 1. In the breathing kagome lattice, the degeneracy between K and K' valleys is lifted. As the gap undergoes sequential closure and reopening in the two valleys, the structural asymmetry and spin-chirality allow for controlled tuning of the topological gap, Chern number, and valley polarization. Moreover, the emergence of a topological Hall effect is is also demonstrated. These findings provide strategies for controlling topological states and advancing applications in quantum devices and valleytronic systems.

cond-mat.mtrl-sci↗

arXiv2023

Janus monolayer TaNF: a new ferrovalley material with large valley splitting and tunable magnetic properties

Materials with large intrinsic valley splitting and high Curie temperature are a huge advantage for studying valleytronics and practical applications. In this work, using first-principles calculations, a new Janus TaNF monolayer is predicted to exhibit excellent piezoelectric properties and intrinsic valley splitting, resulting from the spontaneous spin polarization, the spatial inversion symmetry breaking and strong spin-orbit coupling (SOC). TaNF is also a potential two-dimensional (2D) magnetic material due to its high Curie temperature and huge magnetic anisotropy energy. The effective control of the band gap of TaNF can be achieved by biaxial strain, which can transform TaNF monolayer from semiconductor to semi-metal. The magnitude of valley splitting at the CBM can be effectively tuned by biaxial strain due to the changes of orbital composition at the valleys. The magnetic anisotropy energy (MAE) can be manipulated by changing the energy and occupation (unoccupation) states of d orbital compositions through biaxial strain. In addition, Curie temperature reaches 373 K under only -3% biaxial strain, indicating that Janus TaNF monolayer can be used at high temperatures for spintronic and valleytronic devices.

cond-mat.mtrl-sci↗