%0 Journal Article
%A Freimuth, Frank
%A Blügel, Stefan
%A Mokrousov, Yuriy
%T Band gaps of insulators from moment-functional-based spectral density functional theory
%J Physical review / B
%V 108
%N 16
%@ 2469-9950
%C Woodbury, NY
%I Inst.
%M FZJ-2024-02839
%P 165137
%D 2023
%X Within the method of spectral moments it is possible to construct the spectral function of a many-electron system from the first 2P spectral moments (P=1,2,3,⋯). The case P=1 corresponds to standard Kohn-Sham density functional theory (KS-DFT). Taking P>1 allows us to consider additional important properties of the uniform electron gas (UEG) in the construction of suitable moment potentials for moment-functional-based spectral density functional theory (MFbSDFT). For example, the quasiparticle renormalization factor Z, which is not explicitly considered in KS-DFT, can be included easily. In the four-pole approximation of the spectral function of the UEG (corresponding to P=4) we can reproduce the momentum distribution, the second spectral moment, and the charge response acceptably well, while a treatment of the UEG by KS-DFT reproduces from these properties only the charge response. For weakly and moderately correlated systems we can reproduce the most important aspects of the four-pole approximation by an optimized two-pole model, which leaves out the low-energy satellite band. From the optimized two-pole model we extract parameter-free universal moment potentials for MFbSDFT, which improve the description of the band gaps in Si, SiC, BN, MgO, CaO, and ZnO significantly.
%F PUB:(DE-HGF)16
%9 Journal Article
%R 10.1103/PhysRevB.108.165137
%U https://juser.fz-juelich.de/record/1025376