Yttria stabilized Zirconia: A first principles study

Yttria-stabilized Zirconia is widely used in a variety of different technological fields, for instance as a thermal barrier coating in turbine engines due to its extremely low thermal conductivity. Although it is still a topic of scientific debate, it is generally presumed that its macroscopic properties are strongly related to the dynamics of the occurring oxygen vacancies that are induced due to charge compensation by the aliovalent substitutional doping with Yttrium. Previous ab initio studies were able to shed some light on the complex interactions of these vacancies, but the exact mechanism determining the dynamic processes and thus the thermodynamic properties of this ceramic could not be identified by first principles. By exploiting the availability of massively parallel linear-scaling DFT codes we overcome the numerical limitations affecting these previous studies and thus lay the basis for further multi-scale ab initio studies: We investigate how various fundamental properties of Yttria-stabilized Zirconia depend upon the employed exchange-correlation functional and additionally discuss the implications of these results on the simulation of the thermodynamics of the crystal by inspecting the phonon free energies.