Ultrafast Optical Control of Rashba Interactions in a TMDC Heterostructure

TL;DR

This paper demonstrates how ultrafast optical methods can control Rashba interactions in a TMDC heterostructure, revealing a new spin-depolarization channel for rapid spin manipulation.

Contribution

It provides a microscopic theoretical model and experimental validation of Rashba-induced spin relaxation dynamics in MoSe2/MoS2 heterostructures.

Findings

Rashba interactions dominate spin relaxation above 50 K.

Ultrafast optical control enables rapid spin depolarization.

Identification of a new spin relaxation channel in heterostructures.

Abstract

We investigate spin relaxation dynamics of interlayer excitons in a MoSe2/MoS2 heterostructure induced by the Rashba effect. In such a system, Rashba interactions arise from an out-of-plane electric field due to photo-generated interlayer excitons inducing a phonon-assisted intravalley spin relaxation. We develop a theoretical description based on a microscopic approach to quantify the magnitude of Rashba interactions and test these predictions via time-resolved Kerr rotation measurements. In agreement with the calculations, we find that the Rashba-induced intravalley spin mixing becomes the dominating spin relaxation channel above T = 50 K. Our work identifies a previously unexplored spin-depolarization channel in heterostructures which can be used for ultrafast spin manipulation.