A method for calculating the electronic structure of point defects in nanotubes was developed on the basis of the linear augmented cylindrical wave method. The Green’s function of a defective nanotube was calculated using the Dyson matrix equation. The work was carried out in terms of local density functional theory and the muffin-tin approximation for the electronic potential. Local densities of state were calculated for boron and nitrogen dopants in metal, semimetal, and semiconductor and chiral and non-chiral nanotubes. An increased density of states at the Fermi level was the most significant effect of boron and nitrogen dopants in metal nanotubes. In all semiconductor nanotubes, localized boron states closed the optical band-gap. The effect of nitrogen atoms was restricted to a small rise in local densities of state at the Fermi level.

Electronic Structure of Carbon Nanotubes with  an Impurity Point Defect. D.Z.Kutlubaev, D.V.Makaev, P.N.D’Yachkov: Russian Journal of Inorganic Chemistry, 2011, 56[8], 1301-5