Ab initio calculations were made of the structural, electronic, and magnetic properties of a graphene monolayer substitutionally doped with Co (Cosub) atoms. These calculations were done within density-functional theory using the generalized gradient approximation. Attention was focussed on Co because, among the traditional ferromagnetic elements (Fe, Co and Ni), only Cosub atoms induced spin polarization in graphene. The results revealed the complex magnetism of Co substitutional impurities in graphene, which was mapped into simple models such as the π-vacancy and Heisenberg model. The links established in this work could be used to bring into contact the engineering of nanostructures with the results of π models in defective graphene. In principle, the structures considered here could be fabricated using electron irradiation to create defects and depositing Co at the same time.

Magnetism of Substitutional Co Impurities in Graphene: Realization of Single π Vacancies. E.J.G.Santos, D.Sánchez-Portal, A.Ayuela: Physical Review B, 2010, 81[12], 125433