Electrical Conductivity of Armchair Carbon and Boron Nitride Nanotubes in Tight-binding Model

In this study, within the tight-binding Hamiltonian model, the Green’s function approach, and the Kubo formula, the density of states and the electrical conductivity (EC) of armchair carbon and boron nitride (BN) nanotubes with different diameters are investigated and the results are compared with graphene and BN monolayers. The results show that, contrary tographene, which is a semimetal, armchair carbon nanotubes of any diameter are conductors, while armchair BN nanotubes similar to a BN monolayer are all semiconductors. Also, since it is a semimetal, the EC of graphene is observed to be higher than BN monolayer at all temperatures. In addition, it can be seen that the ECs of both types of nanotubes decrease with increasing diameter and approaches the EC of graphene and BN monolayer becausethe increase in the cross sectionsize provides more lateral ways for electrons to move in transverse directions with respect to the longitudinal axis, and this in turn reduces their mobility along that longitudinal axis. It is also observed that by increasing the diameter, the behaviors of carbon and boron nitride nanotubes respectively approach those of graphene and boron nitride plane.