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, thermal insulation, catalytic properties etc. Within the class of high entropy oxides; rock salt, fluorite, spinel and perovskite phases have been recently synthesized. Complementing these endeavors, the current work explores a method for calculating the stability of high entropy oxides through a collaborative computational and experimental efforts. We construct a nearest neighbor model (NNM) from enthalpies of end member and binary oxides – 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 NNM. Our approach allows us to evaluate potential impurity phases and oxygen vacancy concentration as a function of temperature and oxygen partial pressure, thereby making realistic predictions that can direct and accelerate synthesis of novel multicomponent oxides.