Long-wavelength behavior of the exchange-correlation kernel in the Kohn-Sham theory of periodic systems

Ph Ghosez, X. Gonze, R. Godby

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102 Citations (Scopus)

Abstract

The polarization dependence of the exchange-correlation (xc) energy functional of periodic insulators within Kohn-Sham (KS) density-functional theory requires a (Formula presented) divergence in the xc kernel for small vectors q. This behavior, exemplified for a one-dimensional model semiconductor, is also observed when an insulator happens to be described as a KS metal, or vice versa. Although it can occur in the exchange-only kernel, it is not found in the usual local, semilocal, or even nonlocal approximations to KS theory. We also show that the test-charge and electronic definitions of the macroscopic dielectric constant differ from one another in exact KS theory, but are equivalent in the above-mentioned approximations.

Original languageEnglish
Pages (from-to)12811-12817
Number of pages7
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume56
Issue number20
DOIs
Publication statusPublished - 1997
Externally publishedYes

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