Y Doping: It is evident from Figure (f) that Y La is dominant at E F (∆ H f = ∼ 0.50 eV). This is reasonable considering the +3 charge of both ions in addition to the large ionic radii of both La and Y ions of 1.16 Å and 1.019 Å, respectively. As a charge neutral defect, Y La will not require charge compensation and will only result in more cation disorder in the structure. More surprising is the low formation energy of ∼ 0.78 eV of Y ′