Staggered Superconductivity in UPt$_3$: A New Phenomenological Approach

TL;DR

This paper introduces a new Ginzburg-Landau theoretical model for UPt$_3$ superconductivity, explaining its complex phase diagram and proposing an unconventional staggered order parameter linked to odd-in-time-reversal pairing.

Contribution

It develops a phenomenological multicomponent order parameter model that accounts for UPt$_3$'s phase diagram and suggests a novel staggered superconducting state.

Findings

The model explains the $H-T-P$ phase diagram including the tetracritical point.

It proposes an unconventional staggered superconducting state.

It links the state to odd-in-time-reversal pairing mechanisms.

Abstract

We present a new Ginzburg-Landau theory for superconductivity in UPt$_3$, based upon a multicomponent order parameter transforming under an irreducible space group representation; the phase is staggered in real space. Our model can explain the $H-T-P$ phase diagram including the tetracritical point for all field directions. We motivate this unconventional superconducting state in terms of odd-in-time-reversal pairing that may arise in one- or two-channel Kondo models, and suggest experimental tests.