Nature of substitutional impurity atom B/N in zigzag single-wall carbon nanotubes revealed by first-principle calculations

We present systematic calculations for the single-walled zigzag (n, 0) carbon nanotubes containing the substitutional impurity atom B/N using the ab initio density- functional theory. It is found that the formation energies of the single-walled zigzag carbon nanotubes with substitutional impurity atom B/N depend on the tube diameters as well as the electric properties, and show periodic features. The nature of these periodic features has been revealed, which results from the different bonding structures of the perfect zigzag carbon tubes with different diameters, rather than the defects (substitutional impurity atom B/N) in the zigzag tubes.