Current distribution in B- and N-doped carbon nanotubes

Using density functional theory and Keldysh nonequilibrium Green's functions, we investigate electron current density distribution in molecular electronic devices. In particular, we present the current distribution in pristine (5,5) armchair carbon nanotube as well as in nanotubes with substitutional doping of boron and nitrogen impurity atoms. The presence of impurity breaks the uniformity of current distribution around the carbon rings. For the more electronegative impurity of nitrogen, the current density is attracted toward the side of the tube where the N atom is located; but for the less electronegative impurity of boron, the opposite happens. Accordingly there appears a chiral flow of current in the B- and N-doped armchair nanotube near the impurity.