Effect of spin-dependent tunneling and intervalley scattering in magnetic-semiconductor van der Waals heterostructures on exciton and trion polarization

Abstract

We present a theoretical analysis of valley pseudospin control in the transition metal dichalcogenide (TMD) monolayer by utilizing the magnetic proximity effect of 2D magnetic layer and, propose self-consistent analysis of photoluminescence (PL) polarization peculiarities in TMD/magnetic material van der Waals heterostructures. We attribute observed peculiarities to the interplay between spin-dependent interlayer charge transfer and intervalley scattering of excitons and trions. The ratio between the electron tunneling timescale and the exciton and trion intervalley scattering lifetimes and radiative lifetimes determine the PL dynamics. A possibility to switch PL polarization sign due to the quasi-particles dynamics under circularly polarized laser excitations is revealed. We also discuss generalization of the proposed model due to the careful analysis of both intervalley and intravalley scattering processes between bright and dark excitons. Obtained results allow a long-distance manipulation of exciton and trion behaviors and open the possibilities for the effective control under spin and valley pseudospin in multilayer magnetic-semiconductor van der Waals heterostructures.