Superconductivity with and without glue and the role of the double-occupancy forbidding constraint in the t-J-V model

Abstract

The occurrence of retarded (with glue) and unretarded (without glue) pairing is thoroughly discussed in cuprates. We analyze some aspects of this problem in the context of the t-J-V model in a large-N approximation. When 1/N renormalizations are neglected the mean-field result is recovered, where the unretarded d-wave superconducting pairing triggered by the spin-exchange interaction J is obtained. However, the presence of a non-negligible nearest-neighbors Coulomb interaction V(q) kills superconductivity. If the non-double-occupancy constraint and its fluctuations are considered, the situation changes drastically. In this case, V(q) is screened making d-wave superconductivity very robust. In addition, we show that the early proposal for the presence of an unretarded pairing contribution triggered by the spin-exchange interaction J can be discussed in this context.

19 pages, 3 figures

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Cited by in corpus (2)

• Mean Field Study of Superconductivity in the Square Lattice $t$-$J$ Model with Three-Site Hopping
• Condensation mechanism of high-$T_c$ cuprates: the key role of pairon excitations