Cadmium and indium defects in ceria and their interaction with oxygen vacancies and small polarons.

Abstract

Atomistic simulation calculations have been used to investigate the energetics of defect clustering and migration in ceria. The defects considered are ${\mathrm{In}}^{3+}$, ${\mathrm{Cd}}^{2+}$, their associated oxygen vacancies, and small polarons modeled as ${\mathrm{Ce}}^{3+}$ ions. Thus a range of complex defect clusters is considered. The overall aim of the study is to generate a better understanding of these defects as they relate to recent experimental results obtained using perturbed-angular-correlation spectroscopy. The calculations are successful in this regard, correctly predicting both binding energies and an oxygen migration activation energy. More importantly, the calculations provide an atomistic explanation for certain of the experimental observations. As such, the synergy between calculations and experiment is an important feature of this paper.