Contrast in the Electronic and Magnetic Properties of Doped Carbon and Boron Nitride Nanotubes: A First-Principles Study

We determine atomic and electronic structures of boron- and/or nitrogen-doped carbon nanotubes (CNTs) and carbon-doped boron nitride nanotubes (BN-NTs) of armchair and zigzag types using first-principles pseudopotential-based density functional theory calculations. For comparison, we also determine the atomic and electronic structures of two-dimensional honeycomb lattices of carbon (graphene) and boron nitride. Although carbon doping at either the B or N site in BN-NTs results in anti-ferromagnetically ordered semiconducting state, B or N doping in CNTs gives a simple shift in the Fermi energy and a nonmagnetic state.