Frequency Dependence of the Dielectric Constants and of the Reflectivity   for HfO2 and ZrO2 from First-Principles Calculations
  We present, in this work, our theoretical results for the phonon dispersions and the frequency dependence of the reflectivities and the dielectric constants of ZrO2 and HfO2 in the monoclinic phase. The results show the importance of the lattice contribution for the evaluation of the static dielectric constant. Also, besides the anisotropy shown by these materials along the x and z directions, the zero frequency static dielectric constant decreases with the increasing pressure. 
C. C. Silva, H. W. Leite Alves (DCNAT-Ufsj) and L. M. R. Scolfaro   (IF-Usp)