Second-order central peak in the Raman spectra of disordered ferroelectrics

Authors
Vugmeister, BE Yacoby, Y Toulouse, J Rabitz, H
Citation
Be. Vugmeister et al., Second-order central peak in the Raman spectra of disordered ferroelectrics, PHYS REV B, 59(13), 1999, pp. 8602-8606
Citations number
17
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICAL REVIEW B-CONDENSED MATTER
ISSN journal
01631829 → ACNP
Volume
59
Issue
13
Year of publication
1999
Pages
8602 - 8606
Database
ISI
SICI code
0163-1829(19990401)59:13<8602:SCPITR>2.0.ZU;2-S
Abstract
A theory of the central peak line shape in Raman scattering in ferroelectri cs above T-c is developed. Off-center ions are considered as a possible sou rce of the local symmetry breaking. We argue that in order to properly desc ribe the features of the central peak line shape above T-c one should take into account the second-order invariants in the modulation of the electroni c polarizability by polarization fluctuations. The theory is in excellent a greement with the Raman-scattering experiment in KTa1-xNbxO3 [J. P. Sokolof f, L, L. Chase, and L. A. Boatner, Phys. Rev. B 41, 2398 (1990)]. [S0163-18 29(99)11213-X].