Regensburg 2007 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Oxides and Insulators: Clean Surfaces

O 59.10: Vortrag

Donnerstag, 29. März 2007, 18:00–18:15, H41

Structural and electronic properties of bulk earth alkali oxides and their surfaces — •Björn Baumeier, Peter Krüger, and Johannes Pollmann — Institut für Festkörpertheorie, Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster

Earth alkali oxides play a vital role in a number of technological applications, most prominently as supports in catalysis.

While structural properties of BeO, MgO, CaO, SrO and BaO are quite well described within the local density approximation of density functional theory, the calculated electronic structure suffers from well-known shortcomings, most noticeably the significant underestimate of the band gap and conduction band energies. We present results of DFT calculations using self-interaction-corrected (SIC) pseudopotentials for the aforementioned earth alkali oxides. Bulk electronic properties are in very good agreement with experimental data and – where available – with results of considerably more elaborate quasiparticle calculations. To investigate the properties of nonpolar low-index surfaces of these oxides we apply the very same SIC pseudopotentials and find that the SIC effect on the surface is comparable to that on the bulk electronic structure. The surface bandstructure of MgO(001) resulting within the SIC approach is practically identical to the one resulting from GWA calculations, while the required computational effort in SIC remains at the LDA level. We infer from this good agreement for MgO(001) that our calculations for the other earth alkali oxide surfaces are of similar quality. These results consitute a solid quantitative basis for further studies, e.g., for investigations of optical spectra or adsorbate systems.