Upper limit of spin relaxation in suspended graphene

TL;DR

This paper investigates the fundamental limits of spin relaxation in suspended graphene, revealing that atomic-scale corrugations caused by thermal fluctuations significantly constrain spin lifetimes to around 10 nanoseconds, impacting the design of graphene spintronic devices.

Contribution

The study combines molecular dynamics and quantum transport simulations to identify atomic-scale corrugations as the main factor limiting spin lifetimes in suspended graphene, providing insights for improving spin device performance.

Findings

Thermally-induced atomic corrugations limit spin lifetimes to ~10 ns.

Short-range corrugations are present even in smooth-looking graphene.

Strategies to suppress corrugations could enhance spin lifetimes.

Abstract

We use a combination of molecular dynamics and quantum transport simulations to investigate the upper limit of spin transport in suspended graphene. We find that thermally-induced atomic-scale corrugations are the dominant factor, limiting spin lifetimes to ~10 ns by inducing a strongly-varying local spin-orbit coupling. These extremely short-range corrugations appear even when the height profile appears to be smooth, suggesting they may be present in any graphene device. We discuss our results in the context of experiments, and briefly consider approaches to suppress these short-range corrugations and further enhance spin lifetimes in graphene-based spin devices.