Abstract
Within the method of spectral moments it is possible to construct the spectral function of a many-electron system from the first spectral moments (). The case corresponds to standard Kohn-Sham density functional theory (KS-DFT). Taking 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 , 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 ) 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.
7 More- Received 9 June 2023
- Accepted 6 October 2023
DOI:https://doi.org/10.1103/PhysRevB.108.165137
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