Localized states influence spin transport in epitaxial graphene

TL;DR

This paper presents a model showing how localized states in epitaxial graphene affect spin transport, explaining discrepancies in measured diffusion coefficients and relaxation times.

Contribution

The study introduces a spin transport model incorporating localized states, providing new insights into spin dynamics in epitaxial graphene on SiC(0001).

Findings

Localized states increase effective spin precession frequencies.

Localized states reduce observed spin relaxation times.

Differences in charge and spin diffusion are explained by localized states.

Abstract

We developed a spin transport model for a diffusive channel with coupled localized states that result in an effective increase of spin precession frequencies and a reduction of spin relaxation times in the system. We apply this model to Hanle spin precession measurements obtained on monolayer epitaxial graphene on SiC(0001) (MLEG). Combined with newly performed measurements on quasi-free-standing monolayer epitaxial graphene on SiC(0001) our analysis shows that the different values for the diffusion coefficient measured in charge and spin transport measurements in MLEG and the high values for the spin relaxation time can be explained by the influence of localized states arising from the buffer layer at the interface between the graphene and the SiC surface.