Coexistence of superconductivity and incoherence in quasi 1D chains

TL;DR

This paper reports the discovery of superconductivity in quasi-1D CuO chains, revealing momentum-dependent gaps and spectral features that suggest three-dimensional coherence and challenge previous insulating assumptions.

Contribution

It demonstrates superconductivity in CuO chains via proximity effects and uncovers spectral structures indicating complex pairing mechanisms in layered superconductors.

Findings

Observation of momentum-dependent superconducting gap

Detection of hump-peak-dip spectral structure

Superconductivity arises from proximity effects

Abstract

The dimensionality of a correlated many-body system has a large impact on its electronic properties. When electrons are confined to one-dimensional chains of atoms their behavior is very different than in higher dimensional systems because they become strongly correlated, even in the case of vanishingly small interactions. The chains consisting of copper and oxygen atoms are particularly interesting, because the CuO orbitals are constituents of all known high temperature superconductors. Most of previous spectroscopic studies of CuO chain systems indicated insulating behavior[23-25]. Here we report the discovery of momentum dependent superconducting gap and hump-peak-dip structure in the spectra of the CuO chains. We demonstrate that superconductivity in the chains arises due to proximity effects and the peculiar momentum dependence of the superconducting gap shows how three dimensional coherence emerges in a layered superconductor. The presence of the hump-dip-peak structure in the spectra of the CuO chains is very unexpected as it was thought to only occur in the CuO2 planes and is frequently considered to be a signature of the d-wave pairing and the pairing boson itself.