S-wave Superconductivity in Weak Ferromagnetic Metals

TL;DR

This paper explores the emergence of s-wave superconductivity in weak ferromagnetic metals near the critical point, highlighting the conditions under which superconductivity can occur in such systems.

Contribution

It provides a theoretical analysis showing that weak ferromagnetic metals can host s-wave superconductivity when exchange splitting matches the superconducting gap, and characterizes their Fermi liquid behavior.

Findings

Weak ferromagnetic metals are described by a local ferromagnetic Fermi liquid at low temperatures.

Non-Fermi liquid behavior appears at higher temperatures.

Superconductivity is possible when exchange splitting is comparable to the superconducting gap.

Abstract

We investigate the behavior of weak ferromagnetic metals close to the ferromagnetic critical point. We show that in the limit of small magnetic moment the low temperature metallic phase is rigorously described by a local ferromagnetic Fermi liquid that has a momentum-independent self-energy. Whereas, non-Fermi liquid features develop at higher temperatures. Furthermore, we find that an instability towards s-wave superconductivity is possible when the exchange splitting is comparable to the superconducting gap.