First-principles calculations to describe zirconia pseudopolymorphs

The structural and electronic properties of four different polytypes of zir conia (ZrO2) are studied using ab initio total-energy calculations. The cal culations are performed in the framework of density-functional theory (DFT) and pseudopotential theory. We compare results Obtained within the LDA (lo cal-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 pressur e and temperature. We show that GGC's are necessary to correctly describe t he high-pressure orthorhombic structure of zirconia. The tetragonal-to-cubi c phase transition was studied assuming a martensitic-displacive mechanism following the approach of Jansen [Phys. Rev. B 43, 7267 (1991)].