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 

机构地区：[1]School of Physics,State Key Laboratory of Crystal Materials,Shandong University,Shandanan Street 27,Jinan,250100,China

出　　处：《Nano Research》2021年第3期834-839,共6页纳米研究（英文版）

基　　金：This work is supported by the National Natural Science Foundation of China(No.11804190);Shandong Provincial Natural Science Foundation of China(Nos.ZR2019QA011 and ZR2019MEM013);Shandong Provincial Key Research and Development Program(Major Scientific and Technological Innovation Project)(No.2019JZZY010302);Shandong Provincial Key Research and Development Program(No.2019RKE27004);Qilu Young Scholar Program of Shandong University,and Taishan Scholar Program of Shandong Province.

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 NbX_(2)(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 NbX_(2),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(NbS_(2)∼156 meV/NbSe_(2)∼219 meV),enabling 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 NbX_(2) is switchable via applying moderate strain.These findings make single-layer NbX_(2) tantalizing candidates for realizing high-performance and controllable valleytronic devices.

关 键 词：valley polarization ferromagnetic anomalous valley Hall effect NbX_(2)(X=S Se) FIRST-PRINCIPLES 

分 类 号：O73[理学—晶体学]