Superconductivity in homologous cuprate series: deep oscillations of pairing Coulomb potential

TL;DR

This paper explains how a kinematic constraint causes oscillations in the Coulomb pairing potential, leading to bound pairs and a universal Tc dependence on layer number in multilayer cuprates.

Contribution

It introduces a model linking Coulomb potential oscillations to superconductivity and explains the universal Tc dependence in homologous cuprate series.

Findings

Oscillating pairing potential promotes bound singlet pairs.

Universal Tc dependence explained by interlayer Coulomb interactions.

Kinematic constraints influence pairing in multilayer cuprates.

Abstract

Kinematic constraint arising in the case of superconducting pairing with large momentum results in a cutoff of the screened Coulomb potential excluding large momentum transfers. This leads to a pairing potential oscillating in the real space that ensures a rise of bound singlet pairs. In multilayer cuprates, there is strong Coulomb interaction between particles composing the pair not only in the same cuprate layer but in the neighboring layers as well. In the framework of such a scenario, we explain a universal dependence of the superconducting transition temperature on the number of layers in the unit cell observed in homologous cuprate families.