| Numéro |
J. Phys. Colloques
Volume 42, Numéro C6, Décembre 1981
International Conference on Phonon Physics
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|---|---|---|
| Page(s) | C6-11 - C6-13 | |
| DOI | https://doi.org/10.1051/jphyscol:1981602 | |
International Conference on Phonon Physics
J. Phys. Colloques 42 (1981) C6-11-C6-13
DOI: 10.1051/jphyscol:1981602
Laboratorium für Festkörperphysik, ETH Zürich, 8093 Zürich, Switzerland.
J. Phys. Colloques 42 (1981) C6-11-C6-13
DOI: 10.1051/jphyscol:1981602
PHONON AND ELASTIC ANOMALIES IN INTERMEDIATE VALENT TmxSe AND TmSe1-yTey
M. Celio, R. Monnier et P. WachterLaboratorium für Festkörperphysik, ETH Zürich, 8093 Zürich, Switzerland.
Abstract
In TmxSe and TmSe1-yTey the degree of valence mixing can be adjusted between nearly 3+ for Tm0.87Se and 2.55+ for TmSe0.7Te0.3. The sound velocity vL decreases with increasing degree of valence mixing and the elastic constant c12 becomes negative. The first order Raman spectrum shows an additional peak at 60 cm-1 for strong valence mixing and a softening of the LO (L) frequency. The experiments are compared with the calculation of an 8 parameter shell model resulting in projected density of phonon states.