On the Coulomb interaction in superconducting pairing in cuprates

TL;DR

This paper examines how intersite Coulomb repulsion impacts the superconducting transition temperature in cuprates, comparing different models and highlighting the suppression of s-wave pairing due to strong correlations.

Contribution

It demonstrates that Coulomb repulsion reduces d-wave transition temperature in cuprates across multiple models and explains why s-wave pairing is suppressed in the strong correlation limit.

Findings

Coulomb repulsion lowers d-wave Tc in cuprates.

Intersite Coulomb interaction suppresses superconductivity.

Strong correlations prevent s-wave pairing due to no double occupancy.

Abstract

We discuss a reduction of superconducting transition temperature by the intersite Coulomb repulsion for the d-wave pairing in cuprates. We compare the results found for the spin-fermion model and the extended Hubbard model. We argue that in both the models the d-wave superconducting transition temperature is reduced by the Coulomb repulsion of holes in different unit cells. We also show that in the strong correlation limit the s-wave superconductivity cannot occur due to the kinematic restriction of no double occupancy in the Hubbard subbands.