DFT study of defects in graphene

Defects or imperfections in materials could be extremely useful at the nanoscale level since they could be exploited to modify the properties of nanomaterials for various practical applications. In this paper ab-initio calculations have been performed to study the stability, structural distortions and magnetism caused by defects and dopants in graphene sheet by the creation of vacancies, the inclusion of boron and nitrogen atoms and coexistence of both. All the calculations have been performed by using SIESTA (Spanish Initiative for Electronic Simulations with Thousands of Atoms) code based on density functional theory. Structural optimization shows that introducing a carbon vacancy into a graphene sheet changes the structural distribution of the neighbor atoms. In the case of coexistence of boron (nitrogen) atoms and vacancy, the modified graphene is magnetised only when B (N) atoms locate away from vacancies. These interesting results provide the possibility of tuning the properties according to application of graphene by carefully choosing the shape and size of defects.