Descriptor-based approach for the prediction of cation vacancy formation energies and transition levels

Point defects largely determine the observed optical and electrical properties of a given material, yet the characterization and identification of defects has remained a slow and tedious process, both experimentally and theoretically. We demonstrate a model derived from explicit hybrid functional calculations that can reliably predict the formation energies of cation vacancies as well as the location of their electronic states in a large set of II-VI and III-V materials. Our model uses inputs derived from parameters obtained from the defect-free bulk primitive unit cell consisting of only a few atoms and is found to reproduce the calculated defect transition levels within approximately 0.2 eV. We apply our model to ordered alloys within the CdZnSeTe, CdZnS, and ZnMgO systems and find excellent agreement between the predicted defect charge-state transition levels and those that were explicitly calculated. Our results suggest descriptor-based approaches for predicting point defect formation energies can yield useful accuracy without the need for the expensive and large-scale calculations typically required.