Magnetism in Disordered Graphene and Irradiated Graphite

TL;DR

This study investigates how defects and stacking order influence magnetism in disordered graphene and irradiated graphite, revealing that single-atom defects induce ferromagnetism and stacking order is crucial for magnetic properties.

Contribution

It demonstrates that only single-atom defects can induce ferromagnetism in graphene and highlights the importance of stacking order in magnetic behavior of irradiated graphite.

Findings

Single-atom defects induce ferromagnetism in graphene.

Stacking order is essential for magnetic moments in irradiated graphite.

Ab initio calculations confirm the role of stacking in $\pi$-electron ferromagnetism.

Abstract

The magnetic properties of disordered graphene and irradiated graphite are systematically studied using a combination of mean-field Hubbard model and first-principles calculations. By considering large-scale disordered models of graphene, I conclude that only single-atom defects can induce ferromagnetism in graphene-based materials. The preserved stacking order of graphene layers is shown to be another necessary condition for achieving a finite net magnetic moment of irradiated graphite. Ab initio calculations of hydrogen binding and diffusion and of interstitial-vacancy recombination further confirm the crucial role of stacking order in $\pi$-electron ferromagnetism of proton-bombarded graphite.