| Issue |
J. Phys. Colloques
Volume 42, Number C6, Décembre 1981
International Conference on Phonon Physics
|
|
|---|---|---|
| Page(s) | C6-409 - C6-411 | |
| DOI | https://doi.org/10.1051/jphyscol:19816119 | |
International Conference on Phonon Physics
J. Phys. Colloques 42 (1981) C6-409-C6-411
DOI: 10.1051/jphyscol:19816119
1 Max-Planck-Institut für Festkörperforschung, 7000 Stuttgart-80, F. R. G.
2 Istituto di Fisica dell' Universitá and CNSM-CNR, Milano, Italy
J. Phys. Colloques 42 (1981) C6-409-C6-411
DOI: 10.1051/jphyscol:19816119
MICROSCOPIC POLARIZABILITY MODEL OF FERROELECTRIC SOFT MODES
A. Bussmann-Holder1, G. Benedek2, H. Bilz1 et B. Mokross11 Max-Planck-Institut für Festkörperforschung, 7000 Stuttgart-80, F. R. G.
2 Istituto di Fisica dell' Universitá and CNSM-CNR, Milano, Italy
Abstract
A simplified version of a recent microscopic model of ferroelectric soft modes1 is studied. It is shown that the compensation of long-range and short-range forces2 which induces the soft mode behaviour of ferroelectric systems can be expressed in terms of a simple linear chain model with a non-linear polarizability at the chalcogenide ion lattice site3. This polarizability is equivalent to an on-site electron-two-phonon coupling. The four different temperature regimes which result from the model equations are discussed. The model is applicable to completely different systems such as perovskites, SbSI4, IV-VI5 semiconductors and K2SeO46,7.