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O: Oberflächenphysik

O 32: Nanostrukturen III

O 32.2: Vortrag

Donnerstag, 11. März 2004, 11:30–11:45, H38

Self-organization of Au-nanowires on two-dimensional tungsten carbide — •A. Varykhalov, O. Rader, and W. Gudat — BESSY, 12489 Berlin

A thermally induced formation of well-ordered arrays of Au nanowires on top of the carbon-induced 15×3 reconstruction of W(110) has been discovered with STM and LEED. STM measurements reveal the formation of pairs of nanowires showing a continuous, dense character of the first nanowire and a cluster-like periodic assembly in the internal structure of the second one. Band mapping with angle-resolved photoemission confirmes one-dimensional anisotropy of the electronic structure of the system. Based on quantum size effects observed in photoemission from the valence band of the clean 15×3 surface carbide, a crystallographic model of the substrate relaxation is proposed as explanation for the nanowire geometry. In addition, large chemical shifts in the W4f line permit an element-specific analysis of the self-organized nanowire formation and reveal the possible role of Au-W surface alloying.