Large Proximity-Induced Spin Lifetime Anisotropy in Transition Metal Dichalcogenide/Graphene Heterostructures

TL;DR

This paper demonstrates a significant spin lifetime anisotropy in TMD/graphene heterostructures, revealing enhanced out-of-plane spin lifetime due to proximity-induced spin-valley coupling, with implications for spintronic applications.

Contribution

It provides the first experimental evidence of large spin lifetime anisotropy in TMD/graphene heterostructures caused by proximity effects.

Findings

Out-of-plane spin lifetime is 40 ps, much longer than in-plane (3.5 ps).

Proximity-induced spin-valley coupling affects spin dynamics in graphene.

Demonstrates controllable spin lifetime anisotropy in 2D heterostructures.

Abstract

Van-der-Waals heterostructures have become a paradigm for designing new materials and devices, in which specific functionalities can be tailored by combining the properties of the individual 2D layers. A single layer of transition metal dichalcogenide (TMD) is an excellent complement to graphene (Gr), since the high quality of charge and spin transport in Gr is enriched with the large spin-orbit coupling of the TMD via proximity effect. The controllable spin-valley coupling makes these heterostructures particularly attractive for spintronic and opto-valleytronic applications. In this work, we study spin precession in a monolayer MoSe2/Gr heterostructure and observe an unconventional, dramatic modulation of the spin signal, showing one order of magnitude longer lifetime of out-of-plane spins (40 ps) compared with that of in-plane spins (3.5 ps). This demonstration of a large spin lifetime anisotropy in TMD/Gr heterostructures, is a direct evidence of induced spin-valley coupling in Gr and provides an accessible route for manipulation of spin dynamics in Gr, interfaced with TMDs.