Magnetism and superconductivity driven by identical 4$f$ states in a heavy-fermion metal

TL;DR

This study investigates how magnetism and superconductivity coexist in a heavy-fermion metal, revealing that they originate from different parts of the Fermi surface, allowing a single 4f state to be both localized and itinerant.

Contribution

The paper provides experimental evidence that magnetism and superconductivity can coexist via different Fermi surface regions in a heavy-fermion system, advancing understanding of their interplay.

Findings

Magnetism and superconductivity coexist in the studied material.

They originate from different parts of the Fermi surface.

A single 4f state can be both localized and itinerant.

Abstract

The apparently inimical relationship between magnetism and superconductivity has come under increasing scrutiny in a wide range of material classes, where the free energy landscape conspires to bring them in close proximity to each other. This is particularly the case when these phases microscopically interpenetrate, though the manner in which this can be accomplished remains to be fully comprehended. Here, we present combined measurements of elastic neutron scattering, magnetotransport, and heat capacity on a prototypical heavy fermion system, in which antiferromagnetism and superconductivity are observed. Monitoring the response of these states to the presence of the other, as well as to external thermal and magnetic perturbations, points to the possibility that they emerge from different parts of the Fermi surface. This enables a single 4$f$ state to be both localized and itinerant, thus accounting for the coexistence of magnetism and superconductivity.