Local modulations of the spin-fluctuation mediated pairing interaction by impurities in d-wave superconductors

TL;DR

This paper develops a real-space approach to study how impurities affect the spin-fluctuation mediated pairing interaction in d-wave superconductors, revealing significant local enhancements near impurities.

Contribution

It introduces a self-consistent real-space formulation for inhomogeneous spin and charge susceptibilities within RPA, analyzing impurity effects on pairing interactions.

Findings

Large local enhancement of pairing interaction near impurities

Impurities cause spatial inhomogeneities in pairing strength

Results relate to inhomogeneities observed in cuprate superconductors

Abstract

We present a self-consistent real space formulation of spin-fluctuation mediated d-wave pairing. By calculating all relevant inhomogeneous spin and charge susceptibilities in real space within the random phase approximation (RPA), we obtain the effective pairing interaction and study its spatial dependence near both local potential and hopping impurities. A remarkably large enhancement of the pairing interaction may be obtained near the impurity site. We discuss the relevance of our result to inhomogeneities observed by scanning tunneling spectroscopy on the surface of cuprate superconductors.