Band gaps of crystalline solids from Wannier-localization–based optimal tuning of a screened range-separated hybrid functional

• Published in: Proceedings of the National Academy of Sciences - PNAS 2021-08, Vol.118 (34), p.1-8
• Main Authors: Wing, Dahvyd, Ohad, Guy, Haber, Jonah B., Filip, Marina R., Gant, Stephen E., Neaton, Jeffrey B., Kronik, Leeor
• Format: Article
• Language: English
• Subjects: Crystal structure; Crystallinity; Density functional theory; Electronics industry; Energy gap; Insulators; Ionization; Ionization potentials; Localization; Physical Sciences; Tuning
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2104556118

Accurate prediction of fundamental band gaps of crystalline solid-state systems entirely within density functional theory is a long-standing challenge. Here, we present a simple and inexpensive method that achieves this by means of nonempirical optimal tuning of the parameters of a screened range-separated hybrid functional. The tuning involves the enforcement of an ansatz that generalizes the ionization potential theorem to the removal of an electron from an occupied state described by a localized Wannier function in a modestly sized supercell calculation. The method is benchmarked against experiment for a set of systems ranging from narrow band-gap semiconductors to large band-gap insulators, spanning a range of fundamental band gaps from 0.2 to 14.2 electronvolts (eV), and is found to yield quantitative accuracy across the board, with a mean absolute error of ∼0.1 eV and a maximal error of ∼0.2 eV.