Comparison of local density functionals based on electron gas and finite systems

A widely used approximation to the exchange-correlation functional in density functional theory is the local density approximation (LDA), typically derived from the properties of the homogeneous electron gas (HEG). We previously introduced a set of alternative LDAs constructed from one-dimensional s...

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Bibliographic Details
Published in:Physical review. B 2018-06, Vol.97 (23), Article 235143
Main Authors: Entwistle, M. T., Casula, M., Godby, R. W.
Format: Article
Language:English
Subjects:
Approximation
Density functional theory
Electron gas
Electrons
Exchanging
Mathematical analysis
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Summary:A widely used approximation to the exchange-correlation functional in density functional theory is the local density approximation (LDA), typically derived from the properties of the homogeneous electron gas (HEG). We previously introduced a set of alternative LDAs constructed from one-dimensional systems of one, two, and three electrons that resemble the HEG within a finite region. We now construct a HEG-based LDA appropriate for spinless electrons in one dimension and find that it is remarkably similar to the finite LDAs. As expected, all LDAs are inadequate in low-density systems where correlation is strong. However, exploring the small but significant differences between the functionals, we find that the finite LDAs give better densities and energies in high-density exchange-dominated systems, arising partly from a better description of the self-interaction correction.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.97.235143