The missing atom as a source of carbon magnetism

TL;DR

This study demonstrates that atomic vacancies in graphite can induce local magnetic moments and potentially lead to macroscopic ferrimagnetism, revealing a new source of magnetism in graphene-like materials.

Contribution

It provides experimental and theoretical evidence that isolated atomic vacancies in graphite create electronic resonances and magnetic moments, enabling magnetic state control through vacancy engineering.

Findings

Single vacancies produce sharp electronic resonances at the Fermi level.

Vacancies can induce local magnetic moments in graphite.

Potential to achieve macroscopic ferrimagnetism by vacancy manipulation.

Abstract

Atomic vacancies have a strong impact in the mechanical, electronic and magnetic properties of graphene-like materials. By artificially generating isolated vacancies on a graphite surface and measuring their local density of states on the atomic scale, we have shown how single vacancies modify the electronic properties of this graphene-like system. Our scanning tunneling microscopy experiments, complemented by tight binding calculations, reveal the presence of a sharp electronic resonance at the Fermi energy around each single graphite vacancy, which can be associated with the formation of local magnetic moments and implies a dramatic reduction of the charge carriers' mobility. While vacancies in single layer graphene naturally lead to magnetic couplings of arbitrary sign, our results show the possibility of inducing a macroscopic ferrimagnetic state in multilayered graphene samples just by randomly removing single C atoms.