Ferromagnetic superconductivity driven by changing Fermi surface topology

TL;DR

This paper presents a simple zero-temperature Stoner model explaining ferromagnetic superconductivity in UGe2, where tuning the Fermi level through DOS peaks induces triplet pairing linked to metamagnetic transitions.

Contribution

It introduces a minimal Stoner model connecting Fermi surface topology changes to ferromagnetic superconductivity, inspired by bandstructure calculations.

Findings

Fermi level tuning through DOS peaks induces triplet superconductivity.

Metamagnetic jumps are associated with peaks in the density of states.

The model explains the phase diagram of UGe2 using a quasi-one-dimensional bandstructure.

Abstract

We introduce a simple but powerful zero temperature Stoner model to explain the unusual phase diagram of the ferromagnetic superconductor, UGe2. Triplet superconductivity is driven in the ferromagnetic phase by tuning the majority spin Fermi level through one of two peaks in the paramagnetic density of states (DOS). Each peak is associated with a metamagnetic jump in magnetisation. The twin peak DOS may be derived from a tight-binding, quasi-one-dimensional bandstructure, inspired by previous bandstructure calculations.