Predicting the phase stability of high entropy oxides

High entropy, multicomponent systems are interesting due to the role that cation disorder may play in defining their mechanical, magnetic, reversible energy storage properties, etc. Within the class of high entropy oxides; rocksalt, fluorite, spinel and perovskite phases have all been recently synthesized. Complementing these endeavors, the current work explores a method for calculating the stability of high entropy oxides – compounds in which one cation-site is randomly and equally occupied by five chemical species – through a collaborative computational and experimental efforts. We construct a nearest neighbor (NN) model from enthalpies of mixing of end member oxides and binary oxide mixtures – in their respective potential stable phases – estimated through DFT calculations. The candidates for the high entropy oxides are predicted from the configurational landscapes of the five component oxides, estimated through Monte Carlo simulations using the NN model. Our approach allows us to evaluate potential impurity phases thereby making realistic predictions of novel multicomponent oxides that can be synthesized.