High-Throughput Computational Discovery of Ternary Mixed-Anion Oxypnictides

Mixed-anion materials are still in their infancy compared to the family of homoanionic compounds. However, promising applications including water splitting, battery materials, and thermoelectrics of mixed-anion materials call for an urgent need to explore this growing field. In this work, we screen the experimentally and theoretically reported ternary oxypnictides and determine six prototypes followed by a high-throughput density functional theory study on 1188 MaObXc (M = cation, X = N, P, and As, and a, b, c = integers) compounds. Anharmonic effects are considered to calculate phonon dispersions at finite temperature, with the aim of examining dynamic stabilities. Forty-two hitherto unknown ternary oxypnictides are predicted to be thermodynamically stable and therefore potentially synthesizable. We provide a guidance for experimental synthesis of predicted tungsten oxynitride by constructing a temperature-dependent phase diagram along with the chemical potential map.