Defect Interaction and Deformation in Graphene

Interactions between defects in graphene and the lattice distortion and electronic charge localization induced by the defect interactions are studied by tight-binding (TB) calculations using the recently developed three-center TB potential model. The interaction between two 5-7 Stone-Wales defects gliding along the zig-zag (ZZ) direction of graphene, which has been observed by experiment, is studied at first to validate the TB calculations. Reconstructed divacancy defect pairs and di-adatom defect pairs separated along the glide ZZ and armchair (AC) directions in graphene, respectively, are then studied. We show that the characteristics (i.e., attractive or repulsive) and the strength of interactions between these defects are dependent on the type of defects and on the direction and distance of the defect separation on graphene. Although elastic interaction due to graphene lattice distortion induced by the defect has significant contribution to the total interaction energy, redistribution of electron charges caused by the defects also plays an important role in the defect-defect interaction.