Magnetism of Single Vacancies in Rippled Graphene

Using first-principles calculations, the dependence in the properties of the monovacancy of graphene under rippling controlled by an isotropic strain was determined, with a particular focus on spin moments. At zero strain, the vacancy shows a spin moment of 1.5 μB that increases to ∼2 μB when the graphene is in tension. The changes are more dramatic under compression in that the vacancy becomes nonmagnetic when graphene is compressed more than 2%. This transition is linked to the structural changes that occur around vacancies and is associated with formation of ripples. For compressions slightly greater than 3%, this rippling leads to formation of a heavily reconstructed vacancy structure consisting of two deformed hexagons and pentagons. Our results suggest that any magnetism induced by vacancies that occurs in graphene can be controlled by applying strain.