High-throughput Computational Search for Ternary Oxypnictide Mixed Anion Materials

Mixed anion, or heteroanionic materials (HetMs), have seen a recent resurgence in interest owing to their intriguing properties for a wide range of applications, including photocatalysts, thermoelectrics and transparent conductors. Though HetMs present more degrees of freedom for materials design, only a relatively small amount of HetMs have been reported comparing to single anion materials. By means of high-throughput density functional theory (HT-DFT) computations, combined with the Open Quantum Materials Database (OQMD), new HetMs and their thermodynamic stabilities can be predicted across a wide range of compound chemistries. In this work, HetMs MOX (M is periodic table elements; X=N, P, As) are studied and several promising stable HetMs are found. Both experimentally observed and hypothetical new compounds (in total 438 compounds) are calculated, and analyzed for thermodynamic ground state stability. Phase diagrams with respect to anion chemical potentials are constructed for these potential candidates to provide constraints on the gas-phase temperature and pressure conditions under which these compounds are stable, guiding future experimental synthetic efforts.