Lattice-Dynamic Treatment of Vibrational and Elastic Properties of Cotunnite-Type ZrO2 and HfO2: Comparison with Ambient Pressure Polymorphs

The results of the joint lattice-dynamical model treatment of the vibrational and elastic properties of the cotunnite-type zirconia and hafnia are presented. The model is capable of reproducing the frequencies of the Raman-active vibrations, and provides their symmetry assignment. Also it predicts the position of the infrared-active bands. The model successfully describes the elastic properties of the low-pressure polymorphs, but could not reproduce the bulk modulus of OII-ZrO2 of 332 GPa obtained from a volume-pressure dependence. The current results give an estimate of the bulk modulus of 254 GPa.