Superconducting correlations in the two-band Hubbard model

K. P. Jain; R. Ramakumar; C. C. Chancey

doi:10.1103/PhysRevB.42.2174

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Superconducting correlations in the two-band Hubbard model

K. P. Jain, R. Ramakumar, C. C. Chancey

DOI 10.1103/PhysRevB.42.2174 · Physical Review B

T1

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Abstract

A theoretical study of superconducting correlations in the two-band Hubbard model, corresponding to a narrow copper d band hybridized with a wide oxygen p band, is presented. Assuming that direct superconducting correlations have finite amplitude only in the narrow band, we have applied Hubbard-like decoupling approximations in deriving a generalized superconducting gap function for indirect singlet pairing in the oxygen band. We find this gap to be second order in the hybridization. This gap function interpolates between the weak-coupling (BCS) limit and the intermediate-interaction regime. In the intermediate regime, the gap function scales as the bandwidth of the correlated narrow copper d band. The magnitude of the gap increases with narrow band filling, and our analysis indicates a maximum value in the region of half filling.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3O7 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
La1.85Sr0.15CuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown