Electrical Control of the Valley Magnetic Domain and Anomalous Electron Transport in Bilayer Mo S2

Abstract

In contrast to the valley-selective Berry curvatures of the conduction band of monolayer MoS2, bilayer (2L-) MoS2 (i.e., in 2H-phase) has vanishing Berry curvatures at both K and K′ valleys due to the inversion symmetry. When a vertical electric field is applied to 2L-MoS2, however, conduction bands are split due to a potential difference and the valley-selective Berry curvatures are restored. Especially, for an electron-doped 2L-MoS2, application of a vertical electric field together with an in-plane bias electric field enables one to induce valley magnetization from the valley magnetoelectric effect and further bring about its real-space distribution, i.e., the valley magnetic domain (VMD), through a competition with the valley Hall effect. In particular, the uniaxial strain induces a transfer of electrons from the Q valleys and increases the radii of the electron pockets at the K and K′ valleys. In this context, therefore, at fixed values of the bias field and strain strengths, VMD moving and the consequent modulation of the anomalous transverse current perpendicular to the bias field are found to be achieved via an electrical method, that is, by controlling the vertical electric field. © 2021 American Physical Society.