Dresden 2006 – scientific programme

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O: Oberflächenphysik

O 48: Nanostructures IV

O 48.2: Talk

Friday, March 31, 2006, 11:30–11:45, WIL A317

Nickel Nanowire Formation on Ir(100) — •Andreas Klein, Lutz Hammer, and Klaus Heinz — Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7, D-91058 Erlangen

On the H-induced 5x1 phase of Ir(100) [1], where extended monoatomic Ir chains reside on top of an unreconstructed substrate, the growth of nickel proceeds layerwise up to the sixth layer. Rather unusually, each new layer starts with the development of extended nanowires of several hundred Angstrom length instead of compact islands. Their number first increases, then they locally coalesce into islands until finally the layer is completed. The growth of new wires on a just completed nickel layer always proceeds within shallow troughs which come by the corrugation of the underlying Ni film. The width of the nanowires increases with film thickness, whereby on the xth layer they consist exclusively of (x-1)-
atomic rows. This thickness-dependent size is due to the increasing width of the surface troughs which in turn is caused by local and layer dependent relaxations of the Ni layers above the Ir chains at the Ir-Ni interface. By Ni deposition on the clean reconstructed 5x1-hex phase of Ir(100) the hexagonal reconstruction is lifted ending up in the same local structure than on the 5x1-H phase, yet with considerably poorer long-range order. Consequently, the same nanowires are observed as before, however, with much shorter lengths and an earlier onset of coalescence leading to more compact island structures. [1] L. Hammer, W. Meier, A. Klein, P. Landfried, A. Schmidt, K. Heinz, PRL 91 (2003) 156101