Europhys. Lett.
Volume 47, Number 4, August 1999
Page(s) 462 - 467
Section Condensed matter: structure, mechanical and thermal properties
Published online 01 September 2002
DOI: 10.1209/epl/i1999-00410-4

Europhys. Lett, 47 (4), pp. 462-467 (1999)

Anharmonicity of low-frequency vibrations in a-$\rm Ge{S_2}$ studied by light scattering

M. Yamaguchi 1 and T. Yagi 2

1 Department of Applied Physics, Hokkaido University - Sapporo 060-8628, Japan
2 Research Institute of Electronic Science, Hokkaido University
Sapporo 060-0812, Japan

(received 17 February 1999; accepted 18 June 1999)

PACS. 63.50${\rm +x}$ - Vibrational states in disordered systems.
PACS. 78.30${\rm -j}$ - 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-$\rm Ge{S_2}$). 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