Dielectric-Dependent Range-Separated Hybrid Functional Calculations for Metal Oxides

Recently, we developed a dielectric-dependent range-separated hybrid functional, the screened-exchange range-separated hybrid (SE-RSH) [1], designed to predict the electronic properties of heterogeneous materials. We defined a spatially dependent fraction of exact exchange inspired by the static Coulomb-hole and screened-exchange (COHSEX) approximation used in many-body perturbation theory, and we showed that the SE-RSH functional accurately predicts the electronic structure of several nonmetallic interfaces. Here we extend our work by applying SE-RSH to various oxides, and we assess the performance of the functional by exploring several choices of range-separation parameters. We show that the SE-RSH functional yields good agreement of calculated band gaps with experiments for several oxides, including Al₂O₃, In₂O₃, and SiO₂, as well as transition-metal oxides (e.g., NiO, MnO, and CoO), by accounting for the spatial variation of the screening within the material. We also suggest a simple method for defining range-separation parameters and discuss the importance of using dielectric constants that are determined self-consistently, in order to achieve accurate electronic structure predictions.

[1] J. Zhan, M. Govoni, and G. Galli, J. Chem. Theory Comput. (2023).