The Emergence of Superconductivity in Heavy Electron Materials

TL;DR

This paper introduces a phenomenological BCS-like model for superconductivity in heavy electron materials, explaining the pressure dependence of Tc and predicting a universal dome-shaped Tc behavior in quantum critical superconductors.

Contribution

It provides the first quantitative model for Tc in heavy electron superconductors based on spin fluctuations, extending BCS theory to unconventional materials.

Findings

Model explains pressure dependence of Tc in CeCoIn5 and CeRhIn5

Predicts universal dome-shaped Tc in heavy electron quantum critical superconductors

Offers a physical understanding of spin-fluctuation-mediated pairing in heavy electrons

Abstract

Although the pairing glue for the attractive quasiparticle interaction responsible for unconventional superconductivity in heavy electron materials has been identified as the spin fluctuations that arise from their proximity to a magnetic quantum critical point, there has been no model to describe their superconducting transition at Tc that is comparable to that found by Bardeen, Cooper, and Schrieffer (BCS) for conventional superconductors where phonons provide the pairing glue. Here we propose a phenomenological BCS-like expression for Tc in heavy electron materials, that is based on the unusual properties of the heavy electron normal state from which superconductivity emerges, and a simple model for the effective range and strength of the spin-fluctuation-induced quasiparticle interaction. We show that it provides both a physical explanation and the first quantitative understanding of the pressure-induced variation of Tc in the "hydrogen atoms" of unconventional superconductivity, CeCoIn5 and CeRhIn5, and predicts scaling behavior and a dome-like structure for Tc in all heavy electron quantum critical superconductors.