Strange superconductivity near an antiferromagnetic heavy fermion quantum critical point

TL;DR

This paper proposes a microscopic mechanism for strange superconductivity in heavy fermion materials near an antiferromagnetic quantum critical point, linking Kondo correlations and spin-liquid states to unconventional pairing.

Contribution

It introduces a model based on coexistence and competition of Kondo and antiferromagnetic correlations to explain strange superconductivity and strange metal behavior.

Findings

Coexistence of Kondo and antiferromagnetic correlations explains superconducting features.

The interplay accounts for the emergence of superconductivity from the strange metal state.

Qualitative understanding of phase diagrams near quantum criticality.

Abstract

The heavy fermion CeMIn5 family with M = Co, Rh, Ir provide a prototypical example of strange superconductors with unconventional d-wave pairing and strange metal normal state, emerged near an antiferromagnetic quantum critical point. The microscopic origin of strange superconductor and its link to antiferromagnetic quantum criticality and strange metal state are still open issues. We propose a microscopic mechanism for strange superconductor, based on the coexistence and competition between the Kondo correlation and the quasi-2d short-ranged antiferromagnetic resonating-valence-bond spin-liquid near the antiferromagnetic quantum critical point via a large-N Kondo-Heisenberg model and renormalization group analysis beyond the mean-field level. We find the coexistence (competition) between the two types of correlations well explains the overall features of superconducting and strange metal state. The interplay of these two effects provides a qualitative understanding on how superconductivity emerges from the SM state and the observed superconducting phase diagrams for CeMIn5 near the anti-ferromagnetic quantum critical point.