sp-electron Magnetism in substitutional doped graphene: New insight from first-principles calculations

The study of low-dimensional magnetic systems is a relevant subject in basic research for their potential technological applications. Magnetism on defective graphene has been predicted theoretically and observed experimentally during the last years. However, there are open questions about the origin of the magnetic behavior when substitutional impurities with sp electrons are considered. This work is aimed to contribute to the understanding of impurity-induced magnetism in substitutional doped graphene systems. Total energies, electronic band structures, and spin magnetic moments for doped graphene with impurities introducing holes (B, Al, and Ga) and introducing electrons (N, P, As, Sb, and Bi), were obtained using density functional theory. We show that the spontaneous magnetization in the studied systems arises from an electronic instability by the presence of a narrow impurity band at the Fermi level. In addition, we found that the emergence of magnetism requires the impurity to introduce an extra electron to the graphene lattice. Finally, the relationship between the impurity bandwidth and the impurity-carbon hybridization is analyzed, in the arise of sp-electron magnetism in substitutional doped graphene.