Spin-Orbit-Mediated Spin Relaxation in Graphene

TL;DR

This paper studies how spins relax in intrinsic graphene, highlighting the roles of spin-orbit coupling, ripples, and scattering mechanisms, and discusses the resulting anisotropy and experimental implications.

Contribution

It provides a detailed analysis of spin relaxation mechanisms in graphene, emphasizing the dominance of Dyakonov-Perel and gauge field effects in intrinsic conditions.

Findings

Dyakonov-Perel mechanism dominates spin relaxation

Spin-flip relaxation time inversely proportional to elastic scattering time

Spin relaxation anisotropy depends on competing mechanisms

Abstract

We investigate how spins relax in intrinsic graphene. The spin-orbit coupling arises from the band structure and is enhanced by ripples. The orbital motion is influenced by scattering centers and ripple-induced gauge fields. Spin relaxation due to Elliot-Yafet and Dyakonov-Perel mechanisms and gauge fields in combination with spin-orbit coupling are discussed. In intrinsic graphene, the Dyakonov-Perel mechanism and spin flip due to gauge fields dominate and the spin-flip relaxation time is inversely proportional to the elastic scattering time. The spin relaxation anisotropy depends on an intricate competition between these mechanisms. Experimental consequences are discussed.