Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)

O 41.22: Poster

Dienstag, 23. März 2010, 18:30–21:00, Poster B1

Mosaic and facet structures of epitaxial MnO films on Au(110) — •Klaus Meinel, Michael Huth, Hannes Beyer, Henning Neddermeyer, and Wolf Widdra — Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, Germany

Theoretical studies of rocksalt-like MnO predict for MnO(110) surfaces a (2x1) missing row reconstruction where (100) microfacets run along the [100] direction [1]. For proving this prediction, epitaxial MnO films (thickness 5 - 10 monolayers) have been prepared on an Au(110) substrate and analyzed by means of STM and SPA-LEED. Immediately after film deposition at room temperature, a diffuse background was visible in SPALEED indicating that there is initially poor structural order. Annealing at about 750 K induces long range ordering and relaxation of film structure. Simultaneously, a partly dewetting of the Au(110) substrate occurs. The MnO(110) film displays no (110) terraces. Instead, a furrowed surface is observed with the trenches running parallel to [100]. Along this direction, the film is locally tilted by about +/- 2° due to the misfit which induces a mosaic structure. The surface of the furrows is formed by alternating stripes of (010) and (100) facets having a mean width of about 3 nm. Annealing the films at temperatures around 850 K induces a vanishing of the mosaic structure and an increasing of the width of the (001) facets. Hence, the predicted tendency of (100) faceting is confirmed by experiment. However, the facets are much broader than expected and no (2x1) missing row reconstruction is found within the investigated film thicknesses.

[1] V. Bayer et al., Phys. Rev. B 75, 035404 (2007).