Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 77: Oxides and insulators: Epitaxy and growth

O 77.1: Vortrag

Donnerstag, 25. März 2010, 15:00–15:15, H42

Formation of a laterally nanostructured cobalt oxide — •Matthias Gubo, Christina Ebensperger, Wolfgang Meyer, Lutz Hammer, and Klaus Heinz — Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7, 91058 Erlangen

In this study the growth of ultrathin cobalt oxide on a monolayer cobalt and on a monolayer of a Co₄Ir surface alloy - both prepared on a Ir(100) surface - is investigated by means of low energy electron diffraction (LEED) and scanning tunnelling microscopy (STM). The oxide on a monolayer cobalt reveals a c(4x2) periodic LEED pattern. Its structure consists of a compressively strained CoO(100) layer with cobalt vacancies arranged in a c(4x2) periodicity equivalent to a Co₃O₄ stoichiometry of the film. This structure is very different from the oxide on the bare iridium surface [1]indicating that the internal structure of this cobalt oxide is strongly coupled to the underlying species of atoms (cobalt or iridium, resp.). Accordingly, by growing the oxide on a well ordered Co₄Ir lateral superlattice - produced via decoration of the reconstructed Ir(5x1)-H phase [2] - the cobalt oxide monolayer becomes laterally nanostructured.
So, the oxide’s growth appears to be strongly influenced by the local binding conditions to the substrate. In case of a laterally nanostructured substrate the oxide is nanostructured, too.
M. Gubo et al., J. Phys.: Condens. Matter 21 (2009) 474211 [2] L. Hammer et al., PRL 91 (2003) 156101