A calculation of the thermal expansion of germanium

Publisher Website
Google Scholar
Abstract
The Gruneisen parameters, γ3 j , for a number of the acoustic modes of vibration of Ge have been calculated. The method of calculation is an approximate one which uses the volume dependence of the elastic constants, plus an adjustable parameter which tends to simulate the results of a shell model calculation. The resulting γ3 j for the transverse modes are rapidly varying functions of the wave vector, q. They are positive for small q and negative near the Brillouin zone surface. Optical modes are treated in the Einstein approximation. The calculated γ3 is in good agreement with experiment at all temperatures when optical modes are included. The optical modes contribute appreciably to γ3 at temperatures where their contribution to C v is negligible.

This publication has 15 references indexed in Scilit: