Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 34: Metal Substrates: Structure, Epitaxy and Growth

O 34.8: Poster

Dienstag, 17. März 2015, 18:15–21:00, Poster A

Structural sensitivity of medium energy intensity data in a LEED analysis — •Lutz Hammer, Pascal Ferstl, and M.Alexander Schneider — Solid State Physics, FAU Erlangen-Nürnberg

The crystallographic analysis of complex surface structures involves the quantitative determination of many structural parameters and hence requires a large experimental data base. For a full-dynamical LEED intensity analysis this means that either data sets taken at various angles of incidence have to be used or the energy range of the normal-incidence analysis has to be extended to significantly higher values. We investigated the implications of the second approach by comparing the structural sensitivity of low (50 - 300 eV) and high energy data sets (550 - 800 eV) obtained for different ordered phases of an oxidized or reduced cobalt submonolayer on Ir(100). As expected, the high energy data show a better sensitivity to structural details within deeply buried layers due to the larger penetration depth of the electron wave field. Although the relative scattering contribution of the surface layer is reduced, the the sensitivity towards structural changes at the very surface hardly diminishes. This compensation is caused by the smaller electron wave length at higher energies that provides an increased spatial resolution. The extension of the energy range thus also improves the reliability of the LEED analysis and may lead in favourite cases to structural uncertainties down to a single picometer.