New excitations in quantum paraelectrics

Three remarkable anomalies related to the acoustic branches of quantum paraelectric (QPE) oxides are presented. In SrTiO 3, an additional shear-like sheet is observed for modes propagating in the tetragonal plane, and shear branches polarized parallel to the tetragonal axis show an anomalous softeni...

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Bibliographic Details
Published in:Physica. B, Condensed matter Condensed matter, 1996-04, Vol.219, p.577-580
Main Authors: Courtens, E., Hehlen, B., Coddens, G., Hennion, B.
Format: Article
Language:English
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Summary:Three remarkable anomalies related to the acoustic branches of quantum paraelectric (QPE) oxides are presented. In SrTiO 3, an additional shear-like sheet is observed for modes propagating in the tetragonal plane, and shear branches polarized parallel to the tetragonal axis show an anomalous softening on cooling in the QPE-regime. Both in SrTiO 3 and KTaO 3, a new doublet is observed in Brillouin scattering which is due to second sound, the wave-like propagation of heat. These effects are discussed in terms of large anharmonic polarization clusters.
ISSN:0921-4526
1873-2135
DOI:10.1016/0921-4526(95)00817-9