Ab Initio Study of Interaction between Boron and Nitrogen Dopants in Graphene

We study the interactions between doping boron (B) and nitrogen (N) atoms in graphene. Our calculations are carried out using density functional theory combined with the generalized gradient approximation for the exchange-correlation functional. The total energies, equilibrium geometries, electronic charge distributions, and densities of states of doped graphene sheets are examined in cases of B-B, N-N, and B-N co-doped graphene. The interaction energy between two doping atoms is found to be inversely proportional to the square of the separation distance. We find the B-B and N-N interactions to be repulsive and the B-N interaction to be attractive. The changes in the density of states observed in B- and N-doped graphene are explained in terms of electronic charge transfer.