Density functional calculations combined with thermodynamic modeling were used to investigate defect formation in a perovskite-structured oxide in equilibrium with an O-containing atmosphere. The electronic structure and formation energies for anion and cation vacancies and for Ga, Gd, In, Nd, Sc, and Y dopants incorporated at various lattice sites in BaZrO3 were calculated. On energetic grounds, it was found that most of the investigated dopants (with the possible exception of Nd and Gd) substituted preferentially for Zr atoms in the lattice. The interaction between dopants was found to be repulsive and correlated with the ionic radius of the dopant, while the dopant-O vacancy interaction was found to be attractive. It was also shown that O vacancies were not thermodynamically stable at low temperatures, but formed at the high temperatures and low O partial pressures that were typically used during synthesis of the material.

Thermodynamics of Doping and Vacancy Formation in BaZrO3 Perovskite Oxide from Density Functional Calculations. P.G.Sundell, M.E.Björketun, G.Wahnström: Physical Review B, 2006, 73[10], 104112 (10pp)