Strain Tunable Berry Curvature Dipole, Orbital Magnetization and Nonlinear Hall Effect in WSe_(2) Monolayer  

作　　者：Mao-Sen Qin Peng-Fei Zhu Xing-Guo Ye Wen-Zheng Xu Zhen-Hao Song Jing Liang Kaihui Liu Zhi-Min Liao 秦茂森;朱鹏飞;叶兴国;徐文正;宋振豪;梁晶;刘开辉;廖志敏(State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics,School of Physics,Peking University,Beijing 100871,China)

机构地区：[1]State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics,School of Physics,Peking University,Beijing 100871,China

出　　处：《Chinese Physics Letters》2021年第1期99-104,共6页中国物理快报（英文版）

基　　金：Supported by the National Key Research and Development Program of China(Grant Nos.2018YFA0703703 and 2016YFA0300802);the National Natural Science Foundation of China(Grant Nos.91964201,61825401,and 11774004)。

摘　　要：The electronic topology is generally related to the Berry curvature,which can induce the anomalous Hall effect in time-reversal symmetry breaking systems.Intrinsic monolayer transition metal dichalcogenides possesses two nonequivalent K and K’ valleys,having Berry curvatures with opposite signs,and thus vanishing anomalous Hall effect in this system.Here we report the experimental realization of asymmetrical distribution of Berry curvature in a single valley in monolayer WSe_(2) via applying uniaxial strain to break C_(3v) symmetry.As a result,although the Berry curvature itself is still opposite in K and K’ valleys,the two valleys would contribute equally to nonzero Berry curvature dipole.Upon applying electric field E,the emergent Berry curvature dipole D would lead to an out-of-plane orbital magnetization M ∝ D·E,which further induces an anomalous Hall effect with a linear response to E^(2),known as nonlinear Hall effect.We show the strain modulated transport properties of nonlinear Hall effect in monolayer WSe_(2) with moderate hole-doping by gating.The second-harmonic Hall signals show quadratic dependence on electric field,and the corresponding orbital magnetization per current density M/J can reach as large as 60.In contrast to the conventional Rashba-Edelstein effect with in-plane spin polarization,such current-induced orbital magnetization is along the out-of-plane direction,thus promising for high-efficient electrical switching of perpendicular magnetization.

关 键 词：BERRY CURVATURE MAGNETIZATION 

分 类 号：O469[理学—凝聚态物理]