Zone center phonon frequencies in tetragonal zirconia: lattice dynamical study and new assignment proposition

Abstract

A normal mode calculation of the zone center phonons in the tetragonal structure of ZrO2 compound has been performed with particular emphasis on the low frequency modes. A restricted set of stretching and bending force constants have been introduced and lead to a good agreement between theoretical and experimental Raman and IR phonon frequencies. The Eg symmetry of the two low frequency Raman modes which are involved in the softening process observed with increasing pressure were confirmed and none were left for a low frequency A1g totally symmetric mode as proposed in the literature.