Defect-mediated spin relaxation and dephasing in graphene

TL;DR

This study investigates the causes of spin relaxation in graphene, revealing that magnetic defects are the main source of decoherence, while spin-orbit interactions are negligible, which is crucial for quantum spintronics applications.

Contribution

The paper introduces a quantum interference measurement technique to distinguish magnetic and non-magnetic decoherence sources in graphene, identifying magnetic defects as the primary relaxation mechanism.

Findings

Magnetic defects dominate spin relaxation in graphene.

Spin-orbit interaction in graphene is negligible.

Quantum interference measurement effectively separates decoherence sources.

Abstract

A principal motivation to develop graphene for future devices has been its promise for quantum spintronics. Hyperfine and spin-orbit interactions are expected to be negligible in single-layer graphene. Spin transport experiments, on the other hand, show that graphene's spin relaxation is orders of magnitude faster than predicted. We present a quantum interference measurement that disentangles sources of magnetic and non-magnetic decoherence in graphene. Magnetic defects are shown to be the primary cause of spin relaxation, while spin-orbit interaction is undetectably small.