Predicting Band Gaps with Hybrid Density Functionals

TL;DR

This study evaluates four hybrid density functionals for predicting semiconductor and insulator band gaps, finding that screened hybrids like HSE offer a good balance of accuracy and computational efficiency.

Contribution

It provides a comprehensive comparison of popular hybrid functionals for band gap prediction using a consistent methodology.

Findings

No significant performance difference among the functionals overall.

HSE is more accurate for typical semiconductors.

Including more Hartree-Fock exchange improves HSE's accuracy for large band gap materials.

Abstract

We compare the ability of four popular hybrid density functionals (B3LYP, B3PW91, HSE, and PBE0) for predicting band gaps of semiconductors and insulators over a large benchmark set using a consistent methodology. We observe no significant statistical dference in their overall performance although the screened hybrid HSE is more accurate for typical semiconductors. HSE can improve its accuracy for large large band gap materials --without affecting that of semiconductors-- by including a larger portion of Hartree-Fock exchange in its short range. Given that screened hybrids are computationally much less expensive than their global counterparts, we conclude that they are a better option for the black box prediction of band gaps.