Prediction of bulk modulus at high temperatures from longitudinal phonon frequencies:: Application to diamond, c-BN, and 3C-SiC -: art. no. 024111

A general model relating mechanical and vibrational properties of binary cubic crystals is formulated by the combination of first Szigeti and the Lyddane-Sachs-Teller relations. It is found that a direct correlation is expected to hold between bulk modulus and longitudinal optical phonon frequencies. We apply this model to calculate the bulk modulus of diamond up to 1800 K from available Raman measurements. Our results are in excellent agreement with experimental results derived from Brillouin scattering measurements up to 1600 K. We also apply this model to predict the bulk modulus of c-BN and 3C-SiC, for which no experimental data are available over a range of temperatures. Our predictions agree well with results derived Young modulus measurements and available calculations based on first principles. We discuss practical applications of our model in related scientific fields and possible extensions to study other materials.