Spin and valley filter based on two-dimensional WSe$_2$ heterostructures

TL;DR

This paper explores how external potentials and ac-driving can control spin and valley transport in WSe$_2$ heterostructures, demonstrating tunable polarization effects for potential spintronic and valleytronic applications.

Contribution

It introduces a method to modulate spin and valley polarizations in WSe$_2$ monolayers using gate and ac potentials, highlighting the potential for tunable spin/valley transport devices.

Findings

Gate potentials influence polarization efficiency.

AC potentials enable dynamic control of spin and valley transport.

Double quantum well structures are promising for spin/valley filtering.

Abstract

In this work, we investigate spin and valley transport properties of a WSe$_2$ monolayer placed on top of a ferromagnetic insulator. We are interested in controlling the transport properties by applying external potentials to the system. To obtain spin an valley polarizations, we have considered a single and a double barrier structure with gate potentials. We have analyzed how the efficiency of these polarized transport properties depend on the gate-potential intensities and geometrical configurations. Additionally, we investigate how the spin and valley transport properties are modified when an ac-potential is applied to the system. We have obtained a controllable modulation of the spin and valley polarizations as a function of the intensity and frequency of the ac-potential, mainly in the terahertz range. These results validate the proposal of double quantum well structures of WSe$_2$ as candidates to provide spin and valley dependent transport within an optimal geometrical parameter regime.