Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 18: Poster Session I - MA 141/144 (Atomic Wires; Size-Selected Clusters; Nanostructures; Metal Substrates: Clean Surfaces+Adsorption of Organic / Bio Molecules+Solid-Liquid Interfaces+Adsorption of O and/or H; Surface or Interface Magnetism; Oxides and Insulators: Clean Surfaces)
O 18.78: Poster
Montag, 25. Februar 2008, 18:30–19:30, Poster F
Tensor LEED study of the surface relaxation of SrF2(111) — •Stephan Härtel, Jochen Vogt, and Helmut Weiss — Chemisches Institut der Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, D-39106 Magdeburg
The knowledge about the surface relaxation of other insulators than the alkali halides is comparatively weak yet. Experimental work was carried out for instance for CaF2(111) and BaF2(111) [1] which both crystallize in the fluorite structure. Very often those two compounds are treated together with the homologous material SrF2 but up to now there are no quantitative experimental results available for the surface relaxation of this alkaline earth fluoride. In the present work the SrF2(111) surface was investigated by means of LEED in an energy range from 80 to 320 eV. The recorded I(E) data were analyzed using the tensor LEED approach. The topmost F− layer in the first F-Sr-F triple layer is shifted inward by 0,13±0,07 Å whereas the Sr2+ layer does not exhibit a significant shift. The following F− layer is also relaxed towards the bulk by 0,07±0,07 Å which is in the range of the measuring accuracy. No significant changes of the ion positions in the deeper triple layers were observed. The results are in qualitative good agreement with a theoretical calculation [2] for SrF2(111).
[1] Vogt, J. et al., Surf. Sci. 578 (2005)
[2] Jockisch et al., J. Phys.: Cond. Matt. 5 (1993)