Alloy analog approach and the Gutzwiller approximation as particular cases of a mean-field theory

Journal Article · Tue Oct 20 04:00:00 EDT 1992 · International Journal of Modern Physics B; (United States)

DOI:https://doi.org/10.1142/S021797929200147X· OSTI ID:7155598

Aligia, A A ^[1]; Avignon, M ^[2]

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1. Centro Atomica Bariloche, 8400 Bariloche (Argentina)
2. Univ. Joseph Fourier, L.E.P.E.S., C.N.R.S., BP 166, 38042 Grenoble, Cedex (France)

In this paper, the authors develop a new mean field-theory for systems with on-site correlations, like the Hubbard and Anderson models. It consists in a generalization of the saddle-point approximation to the functional integral representation proposed by Kotliar and Ruckenstein to more than one saddle point. It also contains the alloy analog approximation proposed by Hubbard as a particular case. For a half-filled Hubbard model and a model density of states appropriate for three dimensions, the authors obtain a metal to insulator transition as U increases. The effective Hamiltonian for the insulating phase contains two split bands (rather than only one with an extremely heavy mass) which reproduce correctly the Green's functions of the atomic limit.

• OSTI ID: 7155598
• Journal Information: International Journal of Modern Physics B; (United States), Journal Name: International Journal of Modern Physics B; (United States) Vol. 6:20; ISSN IJPBEV; ISSN 0217-9792
• Country of Publication: United States
• Language: English

Related Subjects

665400* -- Quantum Physics Aspects of Condensed Matter-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CALCULATION METHODS
CRYSTAL MODELS
ELECTRICAL EQUIPMENT
ELECTRICAL INSULATORS
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY-LEVEL DENSITY
EQUIPMENT
FUNCTIONALS
FUNCTIONS
GREEN FUNCTION
HAMILTONIANS
HUBBARD MODEL
INTEGRALS
MATHEMATICAL MODELS
MATHEMATICAL OPERATORS
MEAN-FIELD THEORY
METALS
PHASE TRANSFORMATIONS
QUANTUM OPERATORS
SADDLE-POINT METHOD
THREE-DIMENSIONAL CALCULATIONS