Defective aluminium nitride nanotubes: a new way for spintronics? A density functional study

The structural and electronic properties ( in terms of Mulliken charges, density of states and band structures) of pristine and defective ( 10, 0) AlN nanotubes have been calculated within density functional theory. The results show that, in several defective tubes, a spontaneous spin-polarization arises, due to the presence of spin-split flat bands close to the Fermi level, with a strong localization of the corresponding electronic states and of the magnetic moments. The highest positive spin-magnetization ( 3 mu(B) per cell) is found for the vacancy in the Al site, while the other magnetic tubes ( the vacancy in N, C and O substitutional for N and Al, respectively) show a magnetization of only 1 mu(B) per cell. The spontaneous magnetization of some defective tubes might open the way to their use for spintronic applications.