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O: Fachverband Oberflächenphysik

O 56: Metal substrates: Epitaxy, growth and adsorbates

O 56.14: Vortrag

Donnerstag, 26. März 2009, 18:15–18:30, SCH A316

CuO: template and/or surfactant — •Thorsten Wagner, Thomas Brandstetter, Martin Oehzelt, and Peter Zeppenfeld — Johannes Kepler Universität Linz, Altenberger Str. 69, A-4040 Linz, Österreich

The Cu(1 1 0) surface can be structured readily by adsorbing oxygen: If the coverage of oxygen is less than θ=0.5, the (2×1) reconstructed areas form stripes which are separated by unreconstructed copper areas. These stripes are uniformly distributed and parallel to the [0 0 1]-direction. To extend this one-dimensional template to a two-dimensional array we studied the adsorption of oxygen on a vicinal Cu(19 19 1) surface by means of STM. The steps of this surface are perpendicular to the oxygen stripes. However, the formation of the oxygen reconstruction leads to step bunching and individual terraces are significantly broadened. Therefore the periodicity of the copper template is reduced.[1,2]

On the vicinal and the low index copper surface which were pre-structured by the CuO stripe phase silver was adsorbed at 660K. Although more than a monolayer of silver was added, the total area covered by the CuO phase was preserved. By means of STM, PEEM, and AES we have determined that the step bunches (forming (1 1 1) facets on the vicinal surface) are covered by silver. The experimental results suggest that CuO is acting as a surfactant.

[1] T. Brandstetter et al., Phys. Rev. B 78 (2008) 075402

[2] T. Brandstetter et al., Phys. Rev. B 76 (2007) 245420