Magnetism of substitutional Co impurities in graphene: Realization of single<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>π</mml:mi></mml:math>vacancies

Abstract

We report ab initio calculations of the structural, electronic, and magnetic properties of a graphene monolayer substitutionally doped with $\text{Co}\text{ }({\text{Co}}_{sub})$ atoms. These calculations are done within density-functional theory using the generalized gradient approximation. We focus in Co because among traditional ferromagnetic elements (Fe, Co, and Ni), only ${\text{Co}}_{sub}$ atoms induce spin polarization in graphene. Our results show the complex magnetism of Co substitutional impurities in graphene, which is mapped into simple models such as the $\ensuremath{\pi}$-vacancy and Heisenberg model. The links established in our work can be used to bring into contact the engineering of nanostructures with the results of $\ensuremath{\pi}$ models in defective graphene. In principle, the structures considered here can be fabricated using electron irradiation to create defects and depositing Co at the same time.