Berlin 2012 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 13: Poster II

DF 13.20: Poster

Wednesday, March 28, 2012, 15:00–17:30, Poster E

Light-induced absorption spectroscopy in niobate, titanate and borate crystals — •Andreas Buescher¹, Hauke Bruening¹, Bettina Schoke¹, Christoph Merschjann², Stefan Torbruegge¹, Gabor Corradi³, Susanne Hoffmann-Eifert⁴, and Mirco Imlau¹ — ¹Department of Physics, University of Osnabrück, Germany — ²Helmholtz-Zentrum für Materialien und Energie, Berlin, Germany — ³Research Institute for Solid State Physics and Optics, Budapest, Hungary — ⁴Institut für elektronische Materialien, Forschungszentrum Jülich, Germany

Light-induced absorption spectroscopy (LIAS) is a powerful tool for investigation of wide bandgap oxide materials. In this contribution, we will review the results in the niobates LiNbO₃ and KNbO₃ as well as in SrTiO₃ and β-BaB₂O₄. In LiNbO₃, we study the complex interplay of two-photon excitation of small hole and bound polarons and the optical gating of bipolarons into free and bound polarons. In KNbO₃, we deal with one electron and one hole polaron allowing for the development of a new model for thermally activated polaron hopping giving access to new microscopic parameters. SrTiO₃, widely discussed as a memristor material, is studied using LIAS to get insight into the charge transport properties of this material taking into account the model of extended defects. In β-BaB₂O₄ polarons are discussed as the origin of laser damage. We face the problem as a result of the high photon-flux showing the limitations of this measurement technique.

Financial support by the DFG (IM37/5 and INST190/137-1) and DAAD (50445542) is gratefully acknowledged.