Ferromagnetic semiconductor single-wall carbon nanotubes

Abstract

Possibility of a ferromagnetic semiconductor single wall carbon nanotube\n(SWCNT), where ferromagnetism is due to coupling between doped magnetic\nimpurity on a zigzag SWCNT and electrons spin, is investigate. We found, in the\nweak impurity-spin couplings, at low impurity concentrations the spin up\nelectrons density of states remain semiconductor while the spin down electrons\ndensity of states shows a metallic behavior. By increasing impurity\nconcentrations the semiconducting gap of spin up electrons in the density of\nstates is closed, hence a semiconductor to metallic phase transition is take\nplace. In contrast, for the case of strong coupling, spin up electrons density\nof states remain semiconductor and spin down electron has metallic behavior.\nAlso by increasing impurity spin magnitude, the semiconducting gap of spin up\nelectrons is increased.\n