Spin relaxation in disordered graphene: Interplay between puddles and defect-induced magnetism

TL;DR

This paper investigates how magnetic moments from defects and charge puddles affect spin relaxation in disordered graphene, providing a microscopic model that aligns well with experimental data and explains previously puzzling observations.

Contribution

It introduces a detailed microscopic model for defect-induced spin relaxation in graphene, incorporating charge puddles and spin textures, and offers new insights into experimental phenomena.

Findings

Model accurately predicts spin relaxation times consistent with experiments.

Explains short spin relaxation times in disordered graphene.

Proposes a new interpretation for enhanced relaxation times in hydrogenated graphene.

Abstract

We study the spin relaxation in graphene due to magnetic moments induced by defects. We propose and employ in our studies a microscopic model that describes magnetic impurity scattering processes mediated by charge puddles. This model incorporates the spin texture related to the defect-induced state. We calibrate our model parameters using experimentally-inferred values. The results we obtain for the spin relaxation times are in very good agreement with experimental findings. Our study leads to a comprehensive explanation for the short spin relaxation times reported in the experimental literature. We also propose a new interpretation for the puzzling experimental observation of enhanced spin relaxation times in hydrogenated graphene samples in terms of a combined effect due to disorder configurations that lead to an increased coupling to the magnetic moments and the tunability of the defect-induced $\pi$-like magnetism in graphene.