Magnetism in Graphene Induced by Single-Atom Defects

TL;DR

This study uses first-principles calculations to explore how single-atom defects induce magnetism in graphene, revealing defect-dependent magnetic moments and coupling behaviors relevant to high-temperature magnetic ordering.

Contribution

It provides a detailed first-principles analysis of defect-induced magnetism in graphene, highlighting the role of specific defects and their magnetic interactions.

Findings

Hydrogen chemisorption defects induce 1 μB magnetic moments.

Vacancy defects induce 1.12-1.53 μB magnetic moments.

Magnetic coupling depends on defect sublattice arrangement.

Abstract

We study from first principles the magnetism in graphene induced by single carbon atom defects. For two types of defects considered in our study, the hydrogen chemisorption defect and the vacancy defect, the itinerant magnetism due to the defect-induced extended states has been observed. Calculated magnetic moments are equal to 1 $\mu_B$ per hydrogen chemisorption defect and 1.12$-$1.53 $\mu_B$ per vacancy defect depending on the defect concentration. The coupling between the magnetic moments is either ferromagnetic or antiferromagnetic, depending on whether the defects correspond to the same or to different hexagonal sublattices of the graphene lattice, respectively. The relevance of itinerant magnetism in graphene to the high-$T_C$ magnetic ordering is discussed.