Regensburg 2007 – scientific programme
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O: Fachverband Oberflächenphysik
O 59: Oxides and Insulators: Clean Surfaces
O 59.2: Talk
Thursday, March 29, 2007, 16:00–16:15, H41
Disorder and Complexity in the Surface Structure of Alumina on Ni3Al(111) — •Sebastian Gritschneder1, Holger Schnieder1, Conrad Becker2, Klaus Wandelt2, and Michael Reichling1 — 1Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49069 Osnabrück, Germany — 2Inst. für Phys. u. Theo. Chemie, Universität Bonn, Wegelerstraße 12, 53115 Bonn, Germany
An alumina surface with several outstanding properties is that of a thin film grown on the (111) surface of a Ni3Al substrate. The dominant phase of this oxide film has early been identified as an excellent template for the controlled growth of nanostructures. Templating on the alumina film is facilitated by a dot and a network super-structure that can readily be prepared but have not been understood at the atomic scale. By dynamic force microscopy, we reveal that this phase is build up from a hexagonal lattice of 0.29 nm periodicity, that is commensurate to the aluminum sub-lattice of the substrate. The complex interaction between oxide film and substrate leads to the formation of the two super-structures. By comparison of highly resolved images of the dominant phase with images of another phase of the oxide film, we reveal that their basic structural elements are identical, and therefore we speculate that different substrate conditions are responsible for the adoption of either of the phases.