Slave-boson mean-field theory for the negative- U Hubbard model

Journal Article · Wed Jan 01 00:00:00 EST 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.45.377· OSTI ID:5079157

Sofo, J O; Balseiro, C A ^[1]

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1. Centro Atomico Bariloche and Instituto Balseiro, 8400 Bariloche (Argentina)

We study the negative-{ital U} Hubbard model for arbitrary values of the attractive interaction {ital U} and band filling by means of the slave-boson mean-field theory. We analyze both the normal and the superconducting states. We show that for the superconducting state our approach gives results similar to those obtained in the usual BCS mean field; only small renormalization of the bare parameters are obtained for {ital U} of the order of the bandwidth {ital W}. The energy difference between the normal and the superconducting states is maximum for {ital U}{congruent}{ital W}. This energy difference is a measure of the superconducting critical temperature, which increases exponentially for small {ital U} and decreases as 1/{ital U} for large {ital U}. We discuss briefly the pair-breaking excitations.

• OSTI ID: 5079157
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 45:1; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
SUPERCONDUCTIVITY
MEAN-FIELD THEORY
BCS THEORY
CRITICAL TEMPERATURE
GROUND STATES
HAMILTONIANS
ORDER PARAMETERS
RENORMALIZATION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ENERGY LEVELS
MATHEMATICAL OPERATORS
PHYSICAL PROPERTIES
QUANTUM OPERATORS
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
665411* - Basic Superconductivity Studies- (1992-)