Papers
Topics
Authors
Recent
Gemini 2.5 Flash
Gemini 2.5 Flash
173 tokens/sec
GPT-4o
7 tokens/sec
Gemini 2.5 Pro Pro
46 tokens/sec
o3 Pro
4 tokens/sec
GPT-4.1 Pro
38 tokens/sec
DeepSeek R1 via Azure Pro
28 tokens/sec
2000 character limit reached

Strain effects on topological and valley properties of Janus monolayer $\mathrm{VSiGeN_4}$ (2205.07012v2)

Published 14 May 2022 in cond-mat.mtrl-sci

Abstract: Strain is an effective method to tune the electronic properties of two-dimension (2D) materials, and can induce novel phase transition. Recently, 2D $\mathrm{MA_2Z_4}$ family materials are of interest because of their emerging topological, magnetic and superconducting properties. Here, we investigate the impact of strain effects ($a/a_0$:0.96$\sim$1.04) on the physical properties of Janus monolayer $\mathrm{VSiGeN_4}$ as a derivative of $\mathrm{VSi_2N_4}$ or $\mathrm{VGe_2N_4}$, which possesses dynamical, mechanical and thermal stabilities. For out-of-plane magnetic anisotropy, with increasing strain, $\mathrm{VSiGeN_4}$ undergoes transition between ferrovalley semiconductor (FVS), half-valley-metal (HVM), valley-polarized quantum anomalous Hall insulator (VQAHI), HVM and FVS. These imply twice topological phase transitions, which are related with sign-reversible Berry curvature and band inversion between $d_{xy}$+$d_{x2-y2}$ and $d_{z2}$ orbitals for K or -K valley. The band inversion also leads to transformation of valley splitting strength between valence and conduction bands. However, for in-plane magnetic anisotropy, no special quantum anomalous Hall (QAH) states and valley polarization exist within the considered strain range. The actual magnetic anisotropy energy (MAE) shows no special QAH and HVM states in monolayer $\mathrm{VSiGeN_4}$. Fortunately, these can be easily achieved by external magnetic field, which adjusts the easy magnetization axis of $\mathrm{VSiGeN_4}$ from in-plane one to out-of-plane one. Our findings shed light on how strain can be employed to engineer the electronic states of $\mathrm{VSiGeN_4}$, which may open new perspectives for multifunctional quantum devices in valleytronics and spintronics.

Summary

We haven't generated a summary for this paper yet.