| Citation key |
Ulrich1996 |
| Author |
Ulrich, C. and Mroginski, M. A. and Goni, A. R. and Cantarero, A. and Schwarz, U. and Munoz, V. and Syassen, K. |
| Pages |
121–127 |
| Year |
1996 |
| Journal |
Physica Status Solidi B-Basic Research |
| Volume |
198 |
| Number |
1 |
| Abstract |
The pressure dependence of the phonon modes in the layered semiconductor gamma-InSe has been investigated experimentally and theoretically for pressures up to II GPa. The mode Gruneisen parameters of all Raman-active zone-center phonons have been determined by Raman scattering under pressure. In addition, features corresponding to second and third-order scattering processes are apparent in the Raman spectra under resonance conditions, from which information about zone-edge modes can be obtained. For the assignment of the observed Raman features to vibrational modes we have calculated the phonon dispersion curves using a rigid-ion model including couplings to first-nearest neighbors and long-range Coulomb interaction. At about 7 GPa the sample turns from transparent to opaque and a new Raman mode appears in the spectra at around 165 cm(-1). This is evidence of a pressure-induced structural instability of gamma-InSe, which is optically detected but not by X-ray diffraction. |
