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

M. T. Entwistle*, Michele Casula, R. W. Godby

*Corresponding author for this work

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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.

Original languageEnglish
Article number235143
Pages (from-to)1-8
Number of pages8
JournalPhysical Review B
Issue number23
Publication statusPublished - 25 Jun 2018

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