Valley Edelstein Effect in Monolayer Transition Metal Dichalcogenides

In this work, we predict the emergence of the valley Edelstein Effect (VEE), which is an electric-field-induced spin polarization effect, in gated monolayer transition metal dichalcogenides (MTMDs). We found an unconventional valley-dependent response in which the spin-polarization is parallel to the applied electric field with opposite spin-polarization generated by opposite valleys. This is in sharp contrast to the conventional Edelstein effect in which the induced spin-polarization is perpendicular to the applied electric field. We identify the origin of VEE as combined effects of conventional Edelstein effect and valley-dependent Berry curvatures induced by coexisting Rashba and Ising SOCs in gated MTMDs. Experimental schemes to detect the VEE are also considered.