The Role of Vibrations of Medium-Range Order Clusters in Thermal Conduction of Materials with a Disordered Structure

摘要

A microscopic model that provides a satis factory explanation of hte temperature dependence of the thermal conductivity coefficient for dielectric gallsses in the temperature range above the platesu is proposed for the first time According to this model the transfer fo thermal perturbations occurs through harmonic interaction of oscillators localized at medium-range order clusters with highed bonds It is demonstrated that the interaction coefficient of htese clusters depends on the overlpa integral of the spectral lines attributed to natural vibrations of the clusters whereas the temperature behavior of the thermal conductivy coefficient is governed by the temperature evolution of the vidths of the vibrational lines With due regard for the results of investicgations into the broadening of the vibrational lines the temperature dependence to the thermal conducitity coefficient is calculated in the range 10-500 K.The calulated curve is in good agreement with the experimental data The proposed model accounts for the low thermal conductivity of glasses in the temperaure range under consideration.