Spin dephasing and pumping in graphene due to random spin-orbit interaction

TL;DR

This paper investigates how random spin-orbit interactions in graphene, caused by surface ripples and inhomogeneities, influence spin dephasing, relaxation, and enable electric-field-driven spin manipulation.

Contribution

It demonstrates that random spin-orbit interactions reduce spin dephasing times and facilitate spin control via external electric fields in graphene.

Findings

Random spin-orbit interaction decreases spin relaxation time.

Electric fields can induce spin density through optical transitions.

Spin manipulation is possible over a broad frequency range.

Abstract

We consider spin effects related to the random spin-orbit interaction in graphene. Such a random interaction can result from the presence of ripples and/or other inhomogeneities at the graphene surface. We show that the random spin-orbit interaction generally reduces the spin dephasing (relaxation) time, even if the interaction vanishes on average. Moreover, the random spin-orbit coupling also allows for spin manipulation with an external electric field. Due to the spin-flip interband as well as intraband optical transitions, the spin density can be effectively generated by periodic electric field in a relatively broad range of frequencies.