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Updated: Jul 6, 2025

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating
Published on: April 12, 2018
Tunable valley polarization effect and second-order topological state in monolayer FeClSH
Mengteng Chen1, Xiangru Kong2, Xiao Xie1
1School of Science, Hebei University of Technology, Tianjin 300401, China. linyang.li@hebut.edu.cn.
Abstract:
In two-dimensional (2D) materials, breaking the inversion symmetry plays an important role in valleytronics. Ferrovalley (FV) materials can achieve spontaneous valley polarization (VP) without additional modulation due to the magnetic exchange interaction and strong spin-orbit coupling. Using first-principles calculations, we predict a new 2D material, Janus FeClSH, which exhibits a large spontaneous VP. This monolayer is a perfect FV material, where the valence band maximum and conduction band minimum are located at the K/K' point. A large VP of 102.95 meV is spontaneously generated for the case of out-of-plane magnetization. Additionally, we propose that the irradiating circularly polarized light can be used to realize VP for the case of in-plane magnetization. Remarkably, a triangular nanoflake of FeClSH with armchair edges can show nontrivial corner states, exhibiting a second-order topological insulator (SOTI) state. The VP effect and SOTI state are tunable with the Hubbard U parameter, making the FeClSH monolayer promising for the study of the coupling between VP and SOTI.
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