Hybrid Functional-Based Scissors Operator for Perovskite Oxide Nanostructures: A NaTaO3 Case Study

Accurately predicting the bandgap as well as valence and conduction band positions through theoretical methods is crucial when investigating perovskite oxide nanostructures for a range of applications. Owing mainly to the high computational cost of state-of-the-art electronic structure techniques, using bulk-based scissors operator corrections has become a popular approach. Nonetheless, rigorous analysis concerning its accuracy is of fundamental importance, especially when intrinsic defect states are observed. Through range-separated hybrid functional calculations within the density functional theory framework, the effectiveness of bulk-based scissors operators in correcting both band-edge positions and the bandgap of different NaTaO3 orthorhombic nanostructures has been systematically investigated. Moreover, four distinct approaches were implemented in order to deal with surface-related defect states. The subsequent alignment of each nanostructure's band-edges with water-splitting photocatalytic potentials shows the consistency of bulk-based scissors operators and the importance of a rational method to coherently tackle intrinsic defect levels.