Dresden 2006 – scientific programme

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O: Oberflächenphysik

O 32: Adsorption IV

O 32.6: Talk

Thursday, March 30, 2006, 12:30–12:45, TRE Phys

Nano-ordering of defect structures in disordered Au/Si(111)-(5x2) — •Christoph Seifert, Christian Wiethoff, Frank Meyer zu Heringdorf, and Michael Horn-von Hoegen — Universität Duisburg-Essen, Duisburg, Germany

Au adsorption at elevated temperatures in the Au coverage regime of up to 0.4 ML on Si(111) leads to the formation of (5x2) reconstructed domains. The electron diffraction pattern of this surface resembles that of a (5x1) reconstructed surface with additional pronounced lines at 50% Brillouin-Zone. These lines are well known to be caused by a random phase-shift of adjacent rows of the reconstruction in the two-fold direction[1].

Preparation at temperatures above 500^∘C – in combination with an increased Au coverage – yields a pronounced wavy modulation of these lines with a 20% BZ periodicity, which is visible after cool-down to room-temperature. This modulation is caused by an ordering of neighbouring phase-shifts and thus of the antiphase translational domains as well. A simple model, that qualitatively explains the resulting electron diffraction pattern, will be presented.

[1] Lipson et al. J. Phys. C 7, p.12 (1974)