Superconductivity in the extended two-dimensional Hubbard model: Strong-coupling regime and hybridization effects

Abstract

In this work we have considered a two-dimensional two-band Hubbard model (extended Hubbard model) to study the effect of the nonlocal hybridization Vk on the superconductivity. In the strong-coupling regime and for a d-wave superconducting gap, we have obtained the superconducting critical temperature Tc and the zero-temperature superconducting gap Δ0 for different hybridizations. We have adopted hopping parameters suitable to describe the high-temperature superconductor materials. The results show that for a fixed value of the hybridization and the intraband d−d attractive potential U, the gap increases for low temperatures and diminishes as the temperatures increase toward Tc. As the hybridization increases both, Δ0 and Tc, diminish. For each hybridization, the quantity 2Δ0/kBTc increases and saturates in a particular value as U increases. The relation between applied pressure P and hybridization in the strong-coupling regime is also discussed.

Source-reported materials — not catalogue approval

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