First-principles calculations to describe zirconia pseudopolymorphs

The structural and electronic properties of four different polytypes of zirconia (ZrO2) are studied using ab initio total-energy calculations. The calculations are performed in the framework of density-functional theory (DFT) and pseudopotential theory. We compare results Obtained within the LDA (local-density approximation) and including generalized gradient corrections (GGC's) in the Perdew-Wang and Perdew-Becke formalisms. Within this approach, we are able to predict the correct monoclinic ground state at low pressure and temperature. We show that GGC's are necessary to correctly describe the high-pressure orthorhombic structure of zirconia. The tetragonal-to-cubic phase transition was studied assuming a martensitic-displacive mechanism following the approach of Jansen [Phys. Rev. B 43, 7267 (1991)].