Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 57: Surface dynamics II
O 57.8: Vortrag
Mittwoch, 24. März 2010, 16:45–17:00, H40
Vanadium Oxide on Rh(111): Formation of stripe patterns under reaction conditions — •Florian Lovis1, Ronald Imbihl1, Benjamin Borkenhagen2, and Gerhard Lilienkamp2 — 1Institut f. Physikalische Chemie u. Elektrochemie, Leibniz-Universität Hannover, Callinstr. 3-3A, 30167 Hannover — 2Institut f. Energieforschung u. Physikalische Technologien, Technische Universität Clausthal, Leibniz-Str. 4, 38678 Clausthal-Zellerfeld
Ultrathin films (< 1 ML) of vanadium oxide (VOx) have been deposited on Rh(111). When subjected to the H2 + O2 reaction at 500∘C in the 10−4 mbar range, stripe patterns on a micrometer scale form on the surface, consisting of VOx-covered metal with bare Rh(111) in between. These are investigated under reaction conditions employing PEEM (PhotoEmission Electron Microscopy) and LEEM (Low Energy Electron Microscopy) as spatially resolving methods. The characteristic lenght depends on p and T, while the direction of the stripes on the isotropic Rh(111) surface is controlled by the step direction: While the stripes are initially formed perpendicular to the step direction, certain reaction conditions may also enforce a stripe direction parallel to the step edges. Since the stripe patterns have an intrinsic wavelenght and only form under reaction conditions, they are considered as a Turing-like non-equilibrium structure.