Ab initio study of the influence of adsorbed atoms on vacancy-induced magnetic moments in graphene sheets

TL;DR

This study uses ab initio calculations to explore how adsorbed atoms affect the magnetic moments at vacancies in graphene, revealing various mechanisms for magnetism generation.

Contribution

It provides new insights into how different adsorbed atoms influence vacancy-induced magnetism in graphene through detailed ab initio analysis.

Findings

Vacancies in graphene create magnetic centers with net spin.

Adsorption of H, O, N atoms alters the magnetic properties.

Symmetry breaking effects depend on supercell size.

Abstract

We present ab initio calculations for single-atom vacancies in graphene. In agreement with earlier work, we find that vacancies are responsible for the magnetism recently observed experimentally, creating a center with net spin. For small supercells, there is a strong symmetry breaking in the supercell with respect to the perfect graphene structure, and this symmetry breaking is much smaller for larger supercells. The influence of the adsorption of H, O and N atoms on the spin center of the bare single-atom vacancy and its influence on the magnetism induced in these samples is investigated. A rich variety of mechanisms is found for the generation of magnetism in this system.