Optical probe of ferroelectric order in bulk and thin-film perovskite titanates

Rössle, Matthias; Wang, Chen Nan; Marsik, Premysl; Yazdi-Rizi, M.; Kim, Kyung Wan; Dubroka, Adam; Marozau, Ivan; Schneider, C. W.; Humlíček, J.; Baeriswyl, Dionys; Bernhard, Christian

doi:10.1103/PhysRevB.88.104110

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Journal article

Optical probe of ferroelectric order in bulk and thin-film perovskite titanates

Rössle, Matthias University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland
Wang, Chen Nan University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland
Marsik, Premysl University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland
Yazdi-Rizi, M. University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland
Kim, Kyung Wan University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland - Department of Physics, Chungbuk National University, Korea
Dubroka, Adam University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland - Department of Condensed Matter Physics, Faculty of Science, Masaryk University and Central European Institute of Technology, Brno, Czech Republic
Marozau, Ivan University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland
Schneider, C. W. Paul Scherrer Institut, Villigen, Switzerland
Humlíček, J. Department of Condensed Matter Physics, Faculty of Science, Masaryk University and Central European Institute of Technology, Brno, Czech Republic
Baeriswyl, Dionys University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland
Bernhard, Christian University of Fribourg, Department of Physics and Fribourg Center for Nanomaterials, Switzerland

26.09.2013

Published in:

Physical Review B. - 2013, vol. 88, no. 10, p. 104110

English We have measured the temperature dependence of the direct band gap E_g in SrTiO₃ and BaTiO₃ and related materials with quantum-paraelectric and ferroelectric properties using optical spectroscopy. We show that E_g exhibits an anomalous temperature dependence with pronounced changes in the vicinity of the ferroelectric transition that can be accounted for in terms of the Fröhlich electron-phonon interaction with an optical phonon mode, the so-called soft mode. In addition, we demonstrate that these characteristic changes of E_g can be readily detected even in very thin films of SrTiO₃ with a strain-induced ferroelectric order. Optical spectroscopy thus can be used as a rather sensitive probe of ferroelectric order in very thin films of these titanates and probably also in subsequent multilayers and devices.

Faculty

Faculté des sciences et de médecine

Department

Département de Physique

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