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 μB 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 μB per cell. The spontaneous magnetization of some defective tubes might open the way to their use for spintronic applications.