Scaling behavior of spin transport in hydrogenated graphene

TL;DR

This paper investigates how hydrogenation affects spin transport in graphene, revealing nearly linear scaling of spin relaxation length and sheet resistance with impurity concentration, and clarifying the relaxation mechanism's dependence on doping and impurity levels.

Contribution

It introduces a computational approach combining Landauer-Büttiker formalism with a spin-dependent tight-binding model to analyze spin transport in hydrogenated graphene, addressing previous discrepancies with experimental data.

Findings

Spin relaxation length and sheet resistance scale nearly linearly with impurity concentration.

The spin relaxation mechanism is Markovian near charge neutrality and in the dilute impurity limit.

The method efficiently computes transport properties, providing insights into spin relaxation processes.

Abstract

We calculate the spin transport of hydrogenated graphene using the Landauer-B\"uttiker formalism with a spin-dependent tight-binding Hamiltonian. The advantages of using this method is that it simultaneously gives information on sheet resistance and localization length as well as spin relaxation length. Furthermore, the Landauer-B\"uttiker formula can be computed very efficiently using the recursive Green's function technique. Previous theoretical results on spin relaxation time in hydrogenated graphene have not been in agreement with experiments. Here, we study magnetic defects in graphene with randomly aligned magnetic moments, where interference between spin-channels is explicitly included. We show that the spin relaxation length and sheet resistance scale nearly linearly with the impurity concentration. Moreover, the spin relaxation mechanism in hydrogenated graphene is Markovian only near the charge neutrality point or in the highly dilute impurity limit.