Critical analysis of vacancy-induced magnetism in monolayer and bilayer graphene
The observation of intrinsic magnetic order in graphene and graphene-based materials relies on the formation of magnetic moments and a sufficiently strong mutual interaction. Vacancies are arguably considered the primary source of magnetic moments. Here we present an in-depth density functional theo...
| Autores: | , |
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| Formato: | artículo |
| Fecha de publicación: | 2012 |
| País: | España |
| Recursos: | Universidad Autónoma de Madrid |
| Repositorio: | Biblos-e Archivo. Repositorio Institucional de la UAM |
| Idioma: | inglés |
| OAI Identifier: | oai:repositorio.uam.es:10486/666925 |
| Acesso em linha: | http://hdl.handle.net/10486/666925 https://dx.doi.org/10.1103/PhysRevB.85.245443 |
| Access Level: | acceso abierto |
| Palavra-chave: | Física |
| Resumo: | The observation of intrinsic magnetic order in graphene and graphene-based materials relies on the formation of magnetic moments and a sufficiently strong mutual interaction. Vacancies are arguably considered the primary source of magnetic moments. Here we present an in-depth density functional theory study of the spin-resolved electronic structure of (monoatomic) vacancies in graphene and bilayer graphene. We use two different methodologies: supercell calculations with the SIESTA code and cluster-embedded calculations with the ALACANT package. Our results are conclusive: The vacancy-induced extended π magnetic moments, which present long-range interactions and are capable of magnetic ordering, vanish at any experimentally relevant vacancy concentration. This holds for σ-bond passivated and unpassivated reconstructed vacancies, although, for the unpassivated ones, the disappearance of the π magnetic moments is accompanied by a very large magnetic susceptibility.Only for the unlikely case of a full σ-bond passivation, preventing the reconstruction of the vacancy, a full value of 1 μB for the π extended magnetic moment is recovered for both monolayer and bilayer cases. Our results put on hold claims of vacancy-induced ferromagnetic or antiferromagnetic order in graphene-based systems, while still leaving the door open to σ-type paramagnetism |
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