Berlin 2005 – wissenschaftliches Programm
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DF: Dielektrische Festkörper
DF 10: Elektrische, elektromechanische und optische Eigenschaften
DF 10.3: Vortrag
Dienstag, 8. März 2005, 14:40–15:00, TU EMH225
X-ray diffraction study of the microscopic origin of dielectric and piezoelectric properties in single crystals — •S. Gorfman1,2, V. Tsirelson2, and U. Pietsch1 — 1. Institute of physics, Potsdam University, Am Neuen Palais 2, 14469, Potsdam, Germany — 2Quantum chemistry department, Mendeleev University of Chemical Technology, 121047, Moscow, Russia
The interaction of an external electric field with a crystal generates the number of phenomena, which are of great interest both for industrial applications and fundamental theoretical and experimental research. The aim of this work is to describe the response of the crystal to the external electric field in terms of the electron density and atomic structure - the quantities which can be studied by means of the X-ray diffraction experiment. We developed a lattice dynamical theory of the atomic displacements, induced by the external electric field, and related them to the properties of the phonon spectra and the charge density redistribution inside a crystal. On the basics of this general theory various simplified models have been derived which are appropriate for the analysis of real X-ray diffraction data. The models are validated for data taken from GaPO4 single crystal, where the measurements have been performed at D3 beamline at HASYLAB.