Large and controllable spin-valley splitting in two-dimensional WS2/h-VN heterostructure

Article

关键词: MONOLAYER MOTE2;    POLARIZATION;    TRANSITION;    TRANSPORT;    MOS2;    WSE2;   

DOI  :  10.1103/PhysRevB.100.195435

来源: SCIE

【 摘 要 】

Inspired by the profound physical connotations and potential application prospects of the valleytronics, we design a two-dimensional (2D) WS2/h-VN magnetic van der Waals (vdW) heterostructure and study the control of valley degrees of freedom through the first-principles calculations. A considerable spin splitting of 627 meV is obtained at the K valley, accompanied with a strong suppression of that at the K' valley. An intrinsic large valley splitting of 376 meV is generated in the valence band, which corresponds to an effective Zeeman magnetic field of 2703 T. Besides the valence band, the conduction band of WS2 possesses a remarkable spin splitting also, leading to the possible formation of valley-labeled dark exciton states at the K' valley. The strengths of spin and valley splitting relying on the interfacial orbital hybridization are further tuned continually by the in-plane strain and interlayer spacing. Maximum spin and valley splitting of 654 and 412 meV are finally achieved, respectively, and the effective Zeeman magnetic field can be enhanced to 2989 T with a -3% strain. Time-reversal symmetry breaking and the sizable Berry curvature in the heterostructure lead to a prominent anomalous Hall conductivity at the K and K' valleys. Based on these finding, a prototype filter device for both the valley and spin is proposed.

【 授权许可】

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