A study of the thermal, ionic conductivities and thermotransport of calcia and gadolinia doped zirconia using molecular dynamics simulations

In the present study, 10 mol% concentrations of calcium and gadolinium oxides were chosen as dopants to stabilise zirconium oxide (ZrO2). The main goals of this research were to study the lattice thermal conductivity, oxygen diffusion coefficient, oxygen ionic conductivity and thermotransport of these materials. Therefore, molecular dynamics (MD) simulations based on the Green-Kubo formalism were applied over a wide temperature range (from 800 K to 1800 K) to calculate the thermal and ionic conductivities and thermotransport. These calculations employed a reliable Buckingham type interatomic potential. The integration of an autocorrelation function was applied to calculate the ionic conductivity and, (approximately) the oxygen tracer diffusion coefficient. It was found that the results were in reasonable agreement with available experimental data. The Onsager cross-coefficients (LOq = LqO) were estimated by using the Green-Kubo formalism as well. The results were also compared with the findings of our previous study on yttria-stabilised zirconia (YSZ).