Nitrogen/boron doping position dependence of the electronic properties of a triangular graphene

We investigate the effect of N/B doping on the electronic properties for a zero-dimensional zigzag-edged triangular graphene, wherein two sets of sublattices are unbalanced, using density functional theory (DFT). We find that the substitutional N/B atom energetically prefers to distribute in the major sublattice. After the N/B doping, the net spin for triangular graphene is reduced and full or partial depolarization occurs depending on doping sites. Our DFT calculations show that the triangular graphene with N/B doped in the major sublattice has a larger energy gap, and the electronic properties depend on the doping position. There is an impurity state below or above the Fermi level for the N/B-doped triangular graphene, depending on the sublattice at which the dopant locates. The dependence of the electronic properties on doping position is attributed to the competition between the Coulomb attraction of N(+) (B(-)) and the correlation with nonbonding states for the extra charge introduced by the N/B atom.