DFT Study of Point Defects in Y2O3 Doped with Zirconium

The formation energies of point defects in zirconium-doped yttrium oxide were calculated using density functional theory (DFT). Both substitutional zirconium defects (Zr Y ) and their complexes with native point defects in Y₂O₃ were considered. The results show that zirconium predominantly incorporates into yttrium oxide as Zr⁴⁺ ions, creating positively charged substitutional defects that are compensated by interstitial oxygen ions (O i ²⁻). A considerable fraction of zirconium ions form bound complexes with interstitial oxygen, such as Zr Y –O i pairs and Zr Y –O i –Zr Y ternary defects. These defects are predicted to reduce the lattice parameter, in agreement with experimental observations.