Competition of Orbital Antiferromagnetism With Q-Triplet-Pairing in the Ferromagnetic Superconductor UGe$_2$

TL;DR

This paper investigates the competition between orbital antiferromagnetism and Q-triplet superconductivity in UGe$_2$, highlighting how pressure-induced deviations from nesting influence phase stability and align with experimental observations.

Contribution

It introduces a multicomponent BCS-like model to analyze the interplay of CDW and SC orders in ferromagnetic UGe$_2$, emphasizing the sensitivity to nesting deviations.

Findings

Orbital antiferromagnetism competes with Q-triplet pairing in UGe$_2$.

Pressure causes deviations from nesting, affecting phase stability.

Model predictions align qualitatively with experimental phase diagrams.

Abstract

Within a multicomponent BCS-like framework we study the coexistence and competition of various CDW and SC order parameters in the presence of a strong ferromagnetic background. We find that the competition of unconventional CDW, also called orbital antiferromagnet, with SC at finite momentum (${\bf Q}$-triplet pairing) shows unique characteristics like an extreme sensitivity on the deviations from nesting. We argue that pressure in UGe$_2$ creates deviations from the nesting and report a phase diagram in qualitative agreement with the observed behavior of UGe$_2$.