Valley filter and valley valve based on WSe2 double-barrier junctions modulated by polarized light

Abstract

We demonstrate that an off-resonant circularly polarized light-modulated double-barrier monolayer ${\mathrm{WSe}}_{2}$ junction can operate as a valley filter and a valley valve simultaneously. Spin-, valley-, and energy-dependent line-type resonant peaks appear in the transmission spectrum, and the splitting of the valley degree of freedom due to the coupling between the light-induced gap and the valley index is also present. By fixing the light on the first barrier, the valley switch can be controlled efficiently by the optical field on the second one. Furthermore, the gate voltage can adjust not only the conductance but also the operation window of the valley filter. The proposed junction provides insight into the manipulation of valley degree of freedom based on ${\mathrm{WSe}}_{2}$ and other transition metal dichalcogenides.