Electron spin relaxation in graphene: the role of the substrate

TL;DR

This paper develops a theory for electron spin relaxation in graphene on SiO2, highlighting how substrate-induced effects like impurities and phonons influence spin lifetimes, with implications for spintronics applications.

Contribution

It introduces a theoretical model combining analytical estimates and Monte Carlo simulations to quantify spin relaxation times in graphene due to substrate effects.

Findings

Spin relaxation times range from microseconds to milliseconds.

Spin relaxation is weakly temperature dependent.

Adatoms can drastically reduce spin lifetimes to nanoseconds.

Abstract

Theory of the electron spin relaxation in graphene on the SiO$_2$ substrate is developed. Charged impurities and polar optical surface phonons in the substrate induce an effective random Bychkov-Rashba-like spin-orbit coupling field which leads to spin relaxation by the D'yakonov-Perel' mechanism. Analytical estimates and Monte Carlo simulations show that the corresponding spin relaxation times are between micro- to milliseconds, being only weakly temperature dependent. It is also argued that the presence of adatoms on graphene can lead to spin lifetimes shorter than nanoseconds.