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DF: Dielektrische Festkörper

DF 5: Poster

DF 5.14: Poster

Mittwoch, 10. März 2004, 14:30–18:00, Poster C

Orientation-dependent ELNES of TiO₂: a comparison of theory and experiment — •Christian Heiliger^1,2, Frank Heyroth¹, Frank Syrowatka¹, Wolfram Hergert², and Ingrid Mertig² — ¹Center of Materials Science, Martin-Luther-University Halle-Wittenberg, Hoher Weg 8, 06120 Halle, Germany — ²Martin-Luther-University Halle-Wittenberg, Department of Physics, Von-Seckendorff-Platz 1, 06120 Halle, Germany

In this poster we present a spectroscopic investigation of titanium oxid (TiO₂). The usage of the ultra high vacuum STEM (scanning transmission electron microscope) VG HB 501 equipped with a Gatan Enfina PEELS detector gives the opportunity to detect EELS (electron energy loss spectra) with a high energy resolution. For that reason one can observe characteristic differences in the spectra between the 3 phases of TiO₂: rutile, anatase and brookite. In addition it is possible to investigate the orientation dependence of the samples.

Apart from the experimental discussion a comparison to theoretical calculations is presented. The calculation is based on the DFT (density functional theory) within the LDA (local density approximation) using the Stuttgart-LMTO-47 (linearized muffin tin orbitals) package. Taking into account the core hole effect in the Z+1 or Z+2 approximation a very good agreement in the peak positions is observed. The peak intensities however are not correctly reflected.