Thermal Conduction Mechanisms and Prediction Equations of Thermal Conductivity for Ge–Sb–Te Alloys

Abstract

In this chapter, based on the thermal conductivity and electrical resistivity data obtained in Chaps. 3 and 4, the thermal conduction mechanisms of Sb–Te binary and Sb2Te3–GeTe pseudobinary alloys have been discussed. Both the thermal conductivity and electrical resistivity of Sb2Te3–GeTe pseudobinary alloys show similarity, which is directly related to the structure similarity. According to the structure analysis in this work and research in the literature, the Sb2Te3–GeTe pseudobinary alloys can be considered as solid solution. Therefore, the thermal conduction mechanisms of Sb2Te3–GeTe pseudobinary alloys should be the same. The same case is for Sb-rich Sb–Te alloys. The Wiedemann–Franz (WF) law has been used to predict the electrical thermal conductivity part using the electrical resistivity data. The results show that the free electrons contribute to the most part of the thermal conductivity and the phonon contribution can be neglected. Bipolar diffusion plays an important role at high temperature and accounts for the increase of the thermal conductivity. The exception can be seen in GeTe alloy, which shows metallic properties in the temperature range investigated. The prediction equations have been proposed for the thermal conductivities of Sb–Te binary and Sb2Te3–GeTe pseudobinary alloys. The comparison between the predicted data and experimental data proves that the prediction equations can be used for the industrial applications.