Crystal Features Controlling Oxygen Vacancy Formation in ABO₃ Perovskites

The control of oxygen vacancy (V_O) formation could unlock significant advances in perovskite metal oxide technologies including solar thermochemical fuel and electrochemical fuel/electricity production, multiferroic computer memory, and others. Despite the critical role played by V_Os in determining the performance of such perovskite-oxide-based processes and devices, and the research attention they have garnered over the past few decades, an optimally simple, instructive, and efficient model for their quantitative assessment has been elusive. Here, we introduce a compact linear model for the V_O formation energies of ABO₃ perovskites, where A = {Ca, Sr, Ba, Ce, and La} and B = {Ti, V, Cr, Mn, Fe, Co, and Ni}, in six lattice systems (monoclinic, orthorhombic, tetragonal, rhombohedral, hexagonal, and cubic). The model takes as inputs crystal bond dissociation energies, crystal reduction potentials, band gaps, and energies above the convex hull, which can be obtained from theoretical or experimental databases. Additionally, we demonstrate that the model can be simplified, with acceptable losses in accuracy, such that only crystal bond dissociation energies and crystal reduction potentials are needed. Finally, we present our perspectives on how to improve and extend the model, which already provides both accurate and efficient predictions for high-throughput screening and an intuitive and modular phenomenology for renewable energy applications of metal oxide perovskites and beyond.