Intervalley Scattering of Interlayer Excitons in a MoS$_2$/MoSe$_2$/MoS$_2$ Heterostructure in High Magnetic Field

TL;DR

This study investigates how magnetic fields influence valley polarization and scattering of interlayer excitons in a MoS2/MoSe2/MoS2 heterostructure, advancing valleytronics in 2D materials.

Contribution

It provides new insights into the interplay of exchange interactions and phonon scattering affecting valley polarization under magnetic fields in heterostructures.

Findings

Valley polarization varies non-trivially with magnetic field.

Exchange interaction and phonon scattering govern valley dynamics.

Results inform design of valleytronic devices.

Abstract

Degenerate extrema in the energy dispersion of charge carriers in solids, also referred to as valleys, can be regarded as a binary quantum degree of freedom, which can potentially be used to implement valleytronic concepts in van der Waals heterostructures based on transition metal dichalcogenides. Using magneto-photoluminescence spectroscopy, we achieve a deeper insight into the valley polarization and depolarization mechanisms of interlayer excitons formed across a MoS$_2$/MoSe$_2$/MoS$_2$ heterostructure. We account for the non-trivial behavior of the valley polarization as a function of the magnetic field by considering the interplay between exchange interaction and phonon mediated intervalley scattering in a system consisting of Zeeman-split energy levels. Our results represent a crucial step towards the understanding of the properties of interlayer excitons, with strong implications for the implementation of atomically thin valleytronic devices.