Sign-reversible valley-dependent Berry phase effects in 2D valley-half-semiconductors

• Main Authors: Xiaodong Zhou, Run-Wu Zhang, Zeying Zhang, Wanxiang Feng, Yuriy Mokrousov, Yugui Yao
• Format: Article
• Language: English
• Published: Nature Publishing Group 2021-10-01
• Series: npj Computational Materials
• Online Access: https://doi.org/10.1038/s41524-021-00632-3

Abstract Manipulating valley-dependent Berry phase effects provides remarkable opportunities for both fundamental research and practical applications. Here, by referring to effective model analysis, we propose a general scheme for realizing topological magneto-valley phase transitions. More importantly, by using valley-half-semiconducting VSi2N4 as an outstanding example, we investigate sign change of valley-dependent Berry phase effects which drive the change-in-sign valley anomalous transport characteristics via external means such as biaxial strain, electric field, and correlation effects. As a result, this gives rise to quantized versions of valley anomalous transport phenomena. Our findings not only uncover a general framework to control valley degree of freedom, but also motivate further research in the direction of multifunctional quantum devices in valleytronics and spintronics.