Figure 8. Oxygen vacancy formation energies.

(a) Relative formation energy per oxygen vacancy for several interface configurations and bulk vacancies in ZrO₂ and In₂O₃ as a function of oxygen chemical potential relative to molecular oxygen. The zero energy reference is the corresponding stoichiometric structure. (b) On the basis of first-principles calculations, the formation energy associated with adding an oxygen vacancy to a YSZ-In₂O₃ supercell is predicted to be significantly lower for sites in the interface plane or adjacent to the interface in the In₂O₃ film than for sites in the YSZ substrate. Energies for multiple possible sites for an oxygen vacancy within each plane are shown. Points connected with a line correspond to the lowest energy positions of the vacancy in each plane. The formation energy values are relative to the energy of the lowest energy site in the heterostructure.