First-principles study of transition-metal atoms adsorption on GaN nanotube

We have performed the first-principles calculations onto the adsorption behaviors of 12 transitionmetal (TM) atoms (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pd and Pt) on the surface of the pristine zigzag (8,0) gallium nitride nanotube (GaNNT). The results show that, for Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Pd and Pt, the most stable adsorption sites are all on the top site of the nitrogen atom (N), whereas Ni prefers slightly to the hollow site above the Ga3N3 hexagon ring (H). The binding energies can vary significantly with different TM atoms. This may be related to their number of d electrons. The almost zero binding energy of Zn atom means it can only be physically adsorbed above the N site. The binding energy of Cr is negative (-0.32 eV), indicating the adsorption process is endothermal. The adsorption of TM atoms generally induces some impurity states within the band gap of the pristine GaNNT, except weaker metallic adatom Pd with fully filled 4d electrons of 10. For Cu-adsorbed (8,0) GaNNT, only one type of bands (minority spin) crosses the Fermi level implying the Cu-adsorbed (8,0) GaNNT is half-metal. The certain amount of charge is transferred from the TM atoms to the (8,0) GaNNTs. The Sc-, V-, Cr-, Mn-, Fe-, Co- and Cu-adsorbed (8,0) GaNNT systems have a net magnetic moment from 0.60 (for Cu) to 4.98 (for Mn). These net magnetic moments are located mainly on the TM atoms. (c) 2010 Elsevier B.V. All rights reserved.