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Ab initio DFT study on ferroelectricity on perovskite surfaces and in thin-film capacitors

: Umeno, Y.; Elsässer, C.; Meyer, B.; Gumbsch, P.; Shimada, T.; Kitamura, T.

Gumbsch, P. ; Fraunhofer-Institut für Werkstoffmechanik -IWM-, Freiburg/Brsg.:
Third International Conference Multiscale Materials Modeling 2006. Proceedings : 18 - 22 September 2006, Freiburg, Germany
Stuttgart: Fraunhofer IRB Verlag, 2006
ISBN: 3-8167-7206-4
ISBN: 978-3-8167-7206-4
International Conference Multiscale Materials Modeling (MMM) <3, 2006, Freiburg>
Fraunhofer IWM ()

Ab initio DFT calculations based on the local density approximation were performed to study (a) in-plane polarized ferroelectricity (FE) at PbTiO3 (001) surfaces and (b) thin Pt/PbTiO3/Pt capacitors with perpendicular FE, and their relation with the lateral lattice parameter. A significant influence of lattice parameter on ferroelectricity was found in both cases. At PbTiO3 (001) surfaces, the in-plane FE in [110] direction is stable in both TiO2 and PbO terminations, and it is enhanced by a larger lattice parameter. Antiferrodistortive (AFD) rotation emerging at the PbO-terminated surface is suppressed by a lattice expansion by the competition with FE. Perpendicular FE polarization in Pt/PbTiO3/Pt films is suppressed by a lattice expansion. The critical thickness for ferroelectricity, who se stability is different for TiO2 and PbO terminations of PbTiO3, is obtained as a function of the lateral lattice parameter.