HLE17: An Efficient Way To Predict Band Gaps of Complex Materials

The recently developed high local exchange 2017 (HLE17) exchange correlation functional, which is a local functional with high local exchange, is tested for determining the band gaps of various kinds of semiconductors and insulators, including metal organic frameworks (MOFs), covalent organic frameworks (COFs), perovskites, zeolites, and others. The calculated band gaps are compared to those calculated by more conventional functionals, in particular, Perdew-Burke-Ernzerhof (PBE), PBEsol, PBE+U, and HSE06. The HLE17 functional is found to be more accurate than PBE, PBEsol, and PBE+U and almost as accurate as the much more expensive HSE06. For the MOFs, HLE17 is as accurate as HSE06 with almost 100 times less computational cost. The HLE17 functional is found to be more accurate than the hybrid functional for covalent organic frameworks (COFs), beta-GaSe, and BC3.