Stability and Electronic Properties of a Novel C-BN Heteronanotube from First-Principles Calculations

We report a family of heteronanotubes circumferentially consisting of a curled carbon ribbon and a curled boron nitride ribbon from first-principles calculations. By molecular dynamics simulations and total energy calculations, the stability of the C-BN heteronanotubes (C-BNNTs) is predicted to be comparable to that of carbon nanotubes, and all the C-BNNTs with diameters larger than 0.4 nm are expected to be stable well over room temperature. Zigzag C-BNNTs are found to be direct gap semiconductors with the band gaps varying depending on the tube diameters and the ratio of carbon dimer lines with respect to BN ones. In contrast, armchair C-BNNTs are metallic except for those with diameters less than 0.6 mn or 1-2 axis-oriented zigzag carbon atomic chains around the circumferences, which become semiconducting. The versatile electronic properties in these heteronanotubes originate from an intricate interplay between the quantum confinement effect and the local tube curvature.