Berlin 2018 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 27: Postersession KFM
KFM 27.1: Poster
Donnerstag, 15. März 2018, 15:00–17:00, Poster E
Frequency shifts and Raman signatures at ferroelectric domain interfaces of LiNbO3 and LiTaO3 — Sergej Neufeld1, Michael Rüsing1, •Simone Sanna2, Gerhard Berth1, Artur Zrenner1, and Wolf Gero Schmidt1 — 1Department Physik, Universität Paderborn, 33098 Paderborn, Germany — 2Justus-Liebig-Universität Giessen, Institut für Theoretische Physik, 35392 Gießen, Germany
Periodically poled lithium niobate (LiNbO3, LN) and lithium tantalate (LiTaO3, LT) structures are of particular technological interest as waveguides and SHG structures. The interface between neighboring domains features a large polarization gradient, which is accompanied by a modulation of numerous physical properties such as internal strain, birefringence and Raman cross section. In recent years, several experimental techniques, including Raman spectroscopy [1], have been utilized to image domain walls. In this work, vibrational properties and Raman signatures of LN and LT in the vicinity of domain walls are studied phenomenologically within an atomistic model via density functional theory calculations. Additionally, Raman signatures of LN and LT domain walls are studied experimentally via a confocal Raman setup. The frequency shifts and Raman intensities of E and A1 modes calculated along a phenomenological reaction coordinate between both phases are in qualitative agreement with the measured data. In particular, the well-known soft mode behavior of the low frequency A1-TO1 mode is reproduced in the calculations.
[1] Appl. Phys. B 78, 363-366 (2004)