Optically controlled valley-polarized resonance based on monolayer WSe2 electrical quantum structure

Abstract

In this paper, we propose an asymmetric monolayer WSe2 electrical quantum structure consisting of one well and one barrier. Modulating the chirality and the effective energy of two beams of off-resonant circularly polarized lights (OCPLs), we investigate the optically controlled valley transport properties for electron tunneling through the asymmetric quantum structure. It is found that the perfect valley polarization not only occurs in the case of radiating the homo-chiral OCPLs, but also can be observed with applying the anti-chiral OCPLs. Particularly, when the anti-chiral OCPLs are radiated, the valley-polarized conductance as a function of the effective energy of OCPLs presents the resonant phenomenon, and the amplitude of the resonant peak is enhanced to 1. The results indicate that the valley polarization is conducive to experimental measurement, and the ultra-fast optically controlled valleytronic devices, such as valley-based Flash Memory can be achieved in this quantum structure. Additionally, the optically controlled valley-polarized resonance can be modulated by the intensity of the gate voltage, incident energy and angle.