Europhys. Lett, 47 (4), pp. 462-467 (1999)
Anharmonicity of low-frequency vibrations in a- studied by light scattering
M. Yamaguchi 1 and T. Yagi 2
1 Department of Applied Physics, Hokkaido University - Sapporo 060-8628,
2 Research Institute of Electronic Science, Hokkaido University
Sapporo 060-0812, Japan
(received 17 February 1999; accepted 18 June 1999)
PACS. 63.50 - Vibrational states in disordered systems.
PACS. 78.30 - Infrared and Raman spectra.
PACS. 78.30Ly - Disordered solids.
High-resolution Brillouin and Raman scattering experiments are carried out as a function of pressure (from ambient pressure to 26 kbar) for amorphous germanium disulphide (a-). Large pressure effects are observed for the boson peak spectrum. A comparison of pressure dependences for the boson peak and the longitudinal acoustic (LA) mode is made via the effective third-order elastic stiffness constants determined for both modes. The results indicate larger anharmonic coupling between the low-frequency modes responsible for the boson peak spectra and extended phonons than within extended phonons.
Copyright EDP Sciences