Considerations in the Stability of Ternary Oxide Alloys

Computational high-throughput screening has generated much interest in materials science because of the possibility to guide the development of functional materials along with the ability to enhance the understanding of fundamental properties. Identification of stable crystalline materials for a mixture of two (three) components requires examination of the lowest thermodynamic energy of approximately 2^N (3^N) configurations, where N is the number of atoms in the unit cell. Cluster expansion-based energy functions offer a numerically efficient approach for estimating the stability of new potential alloys. Combining this approach with the nested sampling algorithm, which is a Bayesian Markov chain Monte Carlo method, allows for a one-shot calculation of the phase diagram as a function of composition and temperature. Our results for stable ternary and quaternary mixtures in various crystalline symmetries of group-III oxides with the formula (In_xGa_yAl_z)₂O₃ will be presented. A new stable InGaO₃ compound is reported as a potential transparent conductor material. In addition, the key aspects that determine the stability of these materials will be highlighted.