Electronic properties of the partially hydrogenated armchair carbon nanotubes

Abstract: By means of pseudopotential calculations based on density functional theory (DFT) we studied the effect of hydrogenation on electronic properties of armchair single-wall carbon nanotubes. The calculations demonstrate strong preference for formation of monoatomic H chains along the (5,5) nanotube axis with the H binding in an infinite H chain reaching the value of 2.58 eV per atom. Upon formation of chains of H adatoms, initially metallic (5,5) nanotubes change electronic structure to the semiconducting. The opening of the band gap of $\sim$0.6 eV is accompanied with antiferromagnetic coupling of ferromagnetically ordered magnetic moments on C atoms in vicinity of the H chain. These electronic properties are strikingly similar to those previously observed in narrow graphene nanoribbons with zigzag edges.