Large valley-polarized state in single-layer NbX2 (X =S,Se):Theoretical prediction

• 作者: Yanmei Zang Yandong Ma Rui Peng Hao Wang Baibiao Huang Ying Dai
• 来源期刊: 纳米研究（英文版）
• 年，卷（期）: 2021,（3）
• 所属期刊栏目: Review Articles
• 页码范围: 834-839
• 页数: 6页
• 语种: 英文

摘要

Exploring two-dimensional valleytronic crystals with large valley-polarized state is of considerable importance due to the promising applications in next-generation information related devices.Here,we show first-principles evidence that single-layer NbX2 (X =S,Se) is potentially the long-sought two-dimensional valleytronic crystal.Specifically,the valley-polarized state is found to occur spontaneously in single-layer NbX2,without needing any external tuning,which arises from their intrinsic magnetic exchange interaction and inversion asymmetry.Moreover,the strong spin-orbit coupling strength within Nb-d orbitals renders their valley-polarized states being of remarkably large (NbS2 ～ 156 meV/NbSe2 ～ 219 meV),enalbling practical utilization of their valley physics accessible.In additional,it is predicted that the valley physics (i.e.,anomalous valley Hall effect) in single-layer NbX2 is switchable via applying moderate strain.These findings make single-layer NbX2 tantalizing candidates for realizing high-performance and controllable valleytronic devices.