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TEMPERATURE DEPENDENCE OF GRÜNEISEN’S PARAMETERS IN A SOLID WITH POLYATOMIC BASIS

I. Licea1, A. Ioanid1,*

Affiliation

  1. Faculty of Physics, University of Bucharest, Magurele-Bucharest, R-76900, Romania

Abstract

The temperature dependence of Grüneisen’s parameters Q g T D ac and Q g T E op for acoustic and optical lattice vibrations, as part of total Grüneisen’s parameter in a solid with polyatomic basis is analysed in the frame of the Debye-Einstein approximation. The results are obtained using Debye’s ) (TDQ and Einstein’s ) (TEQ temperatures and the separated theoretical and experimental contributions of the isochoric specific heats ) (T Cac V and ) (T Cop V for acoustic and optical vibrations, respectively. Both Grüneisen’s parameters decrease with the temperature and this behaviour is discussed in the frame of competition between the temperature dependence of vibrational frequencies due to volume change and lattice anharmonicity effects. There are compared the theoretical curves and experimental curves in the case of undoped bismuth silicon oxyde (Bi12SiO20) crystal..

Keywords

Bi12SiO20, Grüneisen’s parameters, Lattice anharmonicity.

Submitted at: March 24, 2004
Accepted at: June 22, 2004

Citation

I. Licea, A. Ioanid, TEMPERATURE DEPENDENCE OF GRÜNEISEN’S PARAMETERS IN A SOLID WITH POLYATOMIC BASIS, Journal of Optoelectronics and Advanced Materials Vol. 6, Iss. 3, pp. 857-864 (2004)