An Alternative Route to D-wave Superconductivity: the Charge Channel

TL;DR

This paper proposes that screened Coulomb interactions in high-temperature cuprate superconductors can naturally lead to d-wave pairing, highlighting the importance of charge interactions over spin channels in the pairing mechanism.

Contribution

It introduces a charge-channel mechanism for d-wave superconductivity driven by the wave-vector structure of the Coulomb interaction, independent of bandstructure effects.

Findings

Charge interactions can induce d-wave pairing in cuprates.

Wave-vector structure at ${f q}=( ext{pi}, ext{pi})$ is crucial.

Coulomb interactions may enhance other pairing mechanisms.

Abstract

We demonstrate that a $d_{x^2-y^2}$ superconducting pairing is naturally associated with the screened Coulomb interaction $V_{eff}({\bf q},\omega)$ within the $CuO_2$ plane of high $T_c$ superconductors. This pairing instability arises (via the dielectric constant) from wave-vector structure in $V_{eff}({\bf q},\omega )$ at ${\bf q}=(\pi,\pi)$, which is associated with 2D Van Hove and local field effects. Our results, which are independent of the bandstructure, suggest that direct Coulomb intereactions are significant (when compared to the spin channel) and will, at the least, enhance any other underlying mechanism for $d_{x^2-y^2}$ wave pairing.