Evidence for granularity, anisotropy and lattice distortions in cuprate superconductors and their implications

TL;DR

This paper reviews evidence of granularity, anisotropy, and lattice distortions in cuprate superconductors, exploring their impact on superconducting mechanisms and the role of electron-lattice interactions.

Contribution

It provides a comprehensive reassessment of experimental evidence linking structural features to superconductivity in cuprates, emphasizing the interplay between lattice effects and electronic properties.

Findings

Granularity affects the phase transition shape.

Superconductivity exhibits three-dimensional characteristics.

Electron-lattice coupling influences superconducting properties.

Abstract

Granularity, anisotropy, local lattice distortions and their dependence on dopant concentration appear to be present in all cuprate superconductors, interwoven with the microscopic mechanisms responsible for superconductivity. Here we review anisotropy and penetration depth measurements to reassess the evidence for granularity, as revealed by the notorious rounded phase transition, the evidence for the three dimensional nature of superconductivity, uncovered by the doping dependence of transition temperature and anisotropy, and to reassess the relevance of the electron-lattice coupling, emerging from the oxygen isotope effects.