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DF: Fachverband Dielektrische Festkörper

DF 2: Dielectric Spectroscopy & Microscopy

DF 2.3: Vortrag

Montag, 23. März 2009, 11:20–11:40, WIL A317

Electronic properties of defects in SrTiO₃ - theory and experiments — •Torsten Weißbach¹, Thomas Riedl², Thomas Gemming², Sibylle Gemming³, Matthias Zschornak¹, Emanuel Gutmann¹, Hartmut Stöcker¹, Tilmann Leisegang¹, and Dirk C. Meyer¹ — ¹Institut für Strukturphysik, TU Dresden — ²Leibniz-Institut für Festkörper-und Werkstoffforschung (IFW) Dresden — ³Forschungszentrum Dresden-Rossendorf

SrTiO₃ is a commercially available wafer material e.g. for the integration of oxide superconductors or microwave filter applications. The electric properties of SrTiO₃ are routinely modified by doping with additional elements such as Nb. A targeted defect engineering may, however, achieve similar or superior results, while remaining in the ternary system (Sr,Ti,O), i.e. without the need for extrinsic doping. Material characterization methods able to distinguish such defects in particular are needed. In the present study we combine all-electron first-principles calculations with electron energy loss and X-ray absorption spectroscopy to study the electronic properties of SrTiO₃-related oxygen deficient compounds. In particular, such changes of the SrTiO₃ core-level spectra are studied, which occur if O vacancies accumulate in SrTiO_(3−δ), or if excess SrO(001) planes are inserted to form Ruddlesden-Popper-type compounds.