INFLUENCE OF POINT-DEFECTS ON THE THERMAL-CONDUCTIVITY OF DIAMOND SINGLE-CRYSTALS - STATE-OF-THE-ART

A new mechanism for the scattering of heat-carrying phonons has been suggested, based on the assumption of the activation of normal processes by isotopes. An attempt is made to explain the high response of the thermal conductivity of diamond single crystals to isotopic impurity concentration. On the basis of the mechanism suggested, the concentration and temperature dependences of the thermal conductivity of diamond have been calculated and compared with the experimental data available. For synthetic industrial diamond made by spontaneous crystallization, the effects of nitrogen impurities and vacancies on thermal conductivity have been estimated. An assumption has been made that nitrogen and vacancy defects are generated as structural elements in the process of diamond synthesis.