Journal ArticleDOI
Applications of Engel and Vosko's generalized gradient approximation in solids.
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TLDR
In this paper, a generalized gradient approximation (GGA) based on the exchange-correlation potential (ECP) was proposed to obtain the equilibrium lattice constants in comparison to experiment, but the total energy aspect is unsatisfactory.Abstract:
Recently, Engel and Vosko have proposed an alternative form of a generalized gradient approximation (GGA) [Phys. Rev. B 47, 13 164 (1993)] within density-functional theory. This version of the GGA (EV93) was obtained by optimizing the exchange-correlation potential ${\mathit{V}}_{\mathrm{xc}}$ instead of the corresponding energy ${\mathit{E}}_{\mathrm{xc}}$. We have applied this functional to various solids and found that equilibrium lattice constants generally are far too large in comparison to experiment, so that the total-energy aspect is unsatisfactory. However, EV93 describes FeO and CoO as antiferromagnetic insulators, while the local-spin-density approximation or the Perdew-Wang version of the GGA yields a metallic ground state. EV93 favors magnetism, e.g., the spin susceptibility of V is increased, but Pd remains nonmagnetic in agreement with experiment.read more
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Journal ArticleDOI
General performance of density functionals.
TL;DR: This review provides a brief outline of the density functional theory and of the historic development of the field, focusing later on the several types of density functionals currently available, and finishing with a detailed analysis of the performance of DFT across a wide range of chemical properties and system types.
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Band gap calculations with Becke?Johnson exchange potential
TL;DR: In this article, a simple analytical form for the exchange potential was proposed by Becke and Johnson, which was shown to reproduce very well the shape of the exact exchange potential (obtained with the optimized effective potential method) for atoms.
Book ChapterDOI
Derivation of a generalized gradient approximation: The PW91 density functional
TL;DR: In this paper, a generalized gradient approximation (GGA) for the exchange and correlation energies was proposed, which satisfied the most important exact conditions respected by LSD, plus several more (but not all) exact conditions currently known.
Journal ArticleDOI
Electronic structure and transport in type-I and type-VIII clathrates containing strontium, barium, and europium
TL;DR: In this article, the thermoelectric properties of filled gallium-germanium clathrates were analyzed from a band-structure point of view using the virtual crystal approximation.
Journal ArticleDOI
Electronic structure of 3d-transition-metal oxides: on-site Coulomb repulsion versus covalency
TL;DR: In this paper, the photoemission core-level spectra are analyzed in terms of a simple cluster model leading to estimates for the charge-transfer energy, the Coulomb correlation energy, and the hybridization strength V. This trend is attributed mostly to the increasing number of empty d states in the early transition metals which enhances the effective metal-ligand hybridization.