Accurate prediction of solid-state electronic and optical excitations from density functional theory

Density functional theory (DFT) has become the work horse of first principles computational chemistry and materials science. Nonetheless, it has struggled, often even qualitatively, in the description of electron and optical spectroscopy. Specifically, research has been fraught for decades with difficult questions as to the extent to which spectroscopic conclusions can be drawn from DFT even in principle, followed by serious concerns as to the reliability of typical approximation in DFT (including time-dependent DFT), especially for the solid state. Here, a novel approach to overcoming these difficulties, involving Wannier-localization based optimal tuning of a screened range-separated hybrid functional, is presented. It is shown that quantitative accuracy for a wide range of semiconductors and insulators is achieved without any empiricism. This opens the door to many DFT-based applications, as well as to a systematic choice of the starting point for GW calculations. Finally, limitations and remaining challenges are discussed.



* This work has been pursued in collaboration with Guy Ohad, Dahvyd Wing, and Maria Camarasa-Gomez (Weizmann Institute of Science), Stephen Gant, Jonah Haber, Francisca Sagredo, and Jeffrey Neaton (UC Berkeley), Marina Filip (U Oxford), and Ashwin Ramasubramaniam (U Amhest).