  Structural, electronic, and optical properties for the cubic, tetragonal, and
monoclinic crystalline phases of ZrO2, as derived from it ab initio
full-relativistic calculations, are presented. The electronic structure
calculations were carried out by means of the all-electron full potential
linear augmented plane wave method, within the framework of the density
functional theory and the local density approximation. The calculated carrier
effective masses are shown to be highly anisotropic. The results obtained for
the real and imaginary parts of the dielectric function, the reflectivity, and
the refraction index, show good agreement with the available experimental
results. In order to obtain the static dielectric constant of ZrO2, we added to
the electronic part, the optical phonons contribution, which leads to values of
e1(0)~29.5, 26.2, 21.9, respectively along the xx, yy, and zz directions, for
the monoclinic phase, in excellent accordance with experiment. Relativistic
effects, including the spin-orbit interaction, are demonstrated to be important
for a better evaluation of the effective mass values, and in the detailed
structure of the frequency dependent complex dielectric function.
