Inhomogeneity-induced enhancement of the pairing interaction in cuprates

TL;DR

This paper proposes a microscopic mechanism explaining how dopant-induced inhomogeneity enhances the pairing interaction in cuprates, supported by observations of local variations in the superconducting gap.

Contribution

It introduces a microscopic model showing that dopant-induced atomic level variations enhance superexchange interactions in cuprates.

Findings

Dopant atoms correlate with increased superconducting gap magnitude.

Spatial variation of atomic levels enhances superexchange interaction.

Mechanism explains positive correlation observed in experiments.

Abstract

Scanning tunneling spectroscopy has recently discovered a positive correlation between the magnitude of the superconducting gap and positions of dopant oxygen atoms in Bi-based cuprates. We propose a microscopic mechanism that could be responsible for this effect. In particular, we demonstrate that the dopant-induced spatial variation of the atomic levels always enhances the superexchange interaction.