Tight-binding calculation studies of vacancy and adatom defects in graphene.

Computational studies of complex defects in graphene usually need to deal with a larger number of atoms than the current first-principles methods can handle. Here, we show that a recently developed three-center tight-binding potential for carbon is very efficient for large scale atomistic simulations and can accurately describe the structures and energies of various defects in graphene. Using the three-center tight-binding potential, we have systematically studied the stable structures and formation energies of vacancy and embedded-atom defects of various sizes up to four vacancies and four embedded atoms in graphene. Our calculations reveal low-energy defect structures and provide a more comprehensive understanding of the structures and stability of defects in graphene.