Electron transport in metallic carbon nanotubes with multiple B and N dopants

Abstract

We report a first-principles investigation of the effects of multiple B and N dopants on the electron transport in metallic carbon nanotubes. Firstly, the effects of two or more B atoms which are randomly or orderly distributed are investigated. Previous study has shown that single B or N dopant gives rise to a transmission valley either below or above the Fermi level. In contrast, we find that in the cases with two B dopants, the transmission valleys can still be observed but the position and the shape of valleys are generally highly dependent on the relative positions of the dopants due to the different interference between the dopants. However, when the nanotube is symmetrically doped with more B atoms along the circumference, the transmission spectra are much more simple. The conductance plateau around the Fermi level is lowered with the increasing dopants. Secondly, the influences of B and N atoms codoping on electronic transport are studied. When one B and one N atom are doped, the effects on the equilibrium conductance of this B-N pair are always negligible. The transmission patterns can be approximately considered as a superposition of the valleys induced by the individual dopants. Especially, when the B and N atoms are nearest neighbors, the valleys induced by the individual dopants may disappear. If more B and N dopants are doped, the corresponding transmission around the Fermi level is very sensitive to how these dopants are distributed. The equilibrium conductance can be suppressed from 2.0 G 0 to 0.3 G 0 in some cases.