A Common Thread: the pairing interaction for the unconventional superconductors

TL;DR

This paper reviews evidence suggesting that spin-fluctuation mediated pairing is a unifying mechanism underlying the unconventional superconductivity observed in cuprates, Fe-based superconductors, and heavy fermion materials.

Contribution

It proposes that spin-fluctuation mediated pairing is the common origin of superconductivity across various unconventional superconductors, based on phenomenological and model studies.

Findings

Neutron resonance signals unconventional pairing

Hubbard models explain observed properties

Spin fluctuations likely mediate pairing

Abstract

The structures, the phase diagrams, and the appearance of a neutron resonance signaling an unconventional superconducting state provide phenomenological evidence relating the cuprates, the Fe-pnictides/chalcogenides as well as some heavy fermion and actinide materials. Single- and multi-band Hubbard models have been found to describe a number of the observed properties of these materials so that it is reasonable to examine the origin of the pairing interaction in these models. In this review, based on the experimental phenomenology and studies of the pairing interaction for Hubbard-like models, it is proposed that spin-fluctuation mediated pairing is the common thread linking a broad class of superconducting materials.