Photoinduced quantum spin and valley Hall effects and orbital magnetization in monolayer MoS2

TL;DR

This paper theoretically shows how off-resonant circularly polarized light can induce 100% valley-polarized transport in monolayer MoS2, affecting conductivity, spin, valley Hall effects, and orbital magnetization, opening new nanoelectronics possibilities.

Contribution

It introduces a method to control valley polarization and related effects in MoS2 using off-resonant light, a novel approach in 2D material optoelectronics.

Findings

Valley-polarized transport can be achieved with off-resonant light.

Enhancement of spin Hall effect and orbital magnetization observed.

Single valley quantum transport enabled by tuning light intensity.

Abstract

We theoretically demonstrate that 100\% valley-polarized transport in monolayers of MoS$_{2}$ and other group-VI dichalcogenides can be obtained using off-resonant circularly polarized light. By tuning the intensity of the off-resonant light the intrinsic band gap in one valley is reduced, while it is enhanced in the other valley, enabling single valley quantum transport. As a consequence, we predict (i) enhancement of the longitudinal electrical conductivity, accompanied by an increase in the spin-polarization of the flowing electrons, (ii) enhancement of the intrinsic spin Hall effect, together with a reduction of the intrinsic valley Hall effect, and (iii) enhancement of the orbital magnetic moment and orbital magnetization. These mechanisms provide appealing opportunities to the design of nanoelectronics based on dichalcogenides.