SKM 2023 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 14: Polar Oxide Crystals and Solid Solutions II
KFM 14.6: Vortrag
Donnerstag, 30. März 2023, 15:55–16:15, POT 106
Small polaron absorption centers in lithium noibate-tantalate solid solutions — •Anton Pfannstiel1, Simone Sanna2, Yuriy Suhak3, and Steffen Ganschow4 — 1Inst. Physics, Osnabrück University — 2Inst. Theoretical Physics, University of Gießen — 3Inst, Energy Research, Technical university of Clausthal — 4Leibniz-Institut für Kristallzüchtung (IKZ), Berlin
The study of small polarons in ferroelectric lithium niobate (LN) enabled the understanding of various physical phenomena on a microscopic level, like photo-induced coloration or conductivity and led to the formulation of a robust model of polaronic localization centers and energies [O. F. Schirmer et al 2009 J Phys.: Condens. Matter 21 123201]. So far, for lithium tantalate (LT) and the solid solution, lithium niobate-tantalate (LNT) a respective small polaron model is missing in literature.
For this purpose, this study provides polaron self localization energies for LN, LT and LNT crystals of various composition. Thermally reduced crystals are optically bleached at cryogenic temperatures. The resulting small polaron absorption bands are identified through transmission spectroscopy and modeled within the framework of small polaron absorption theory. The determined polaron energies are interpreted against the background of the known defect models for LN and LT but also in conjunction with ab-initio modeling results for carrier self-localization. Financial support by the DFG [projects IM 37/12-1, SA 1948/3-1, SU 1261/1-1, GA 2403/7-1, FOR5044] is gratefully acknowledged.