Boron nitride and carbon double-wall hetero-nanotubes: first-principles calculation of electronic properties.

First-principles calculations based on density functional theory with the generalized gradient approximation were carried out to investigate the electronic properties of boron nitride and carbon double-wall hetero-nanotubes of different chirality and size. The results show that the electronic structures of the double-wall hetero-nanotubes near the Fermi level are dominated by the p electrons of carbon atoms, regardless of whether the carbon nanotube is inside or outside the boron nitride nanotube. Double-wall hetero-nanotubes consisting of semiconducting carbon and boron nitride nanotubes are semiconductors. An opening of a band gap is observed for armchair carbon and boron nitride double-wall hetero-nanotubes with small intertube spacing due to the intertube interaction and the changes of symmetry.