Topological hydrodynamics in spin-triplet superconductors

TL;DR

This paper explores the topological hydrodynamics of spin-triplet superconductors, linking supercurrent circulation to magnetic skyrmion density, and proposes a novel SQUID device to detect ferromagnetic spin-triplet superconductivity.

Contribution

It introduces a blueprint for a spin-triplet superconducting SQUID that detects topological spin textures without a Josephson junction.

Findings

Proposal of a spin-triplet SQUID with nonsingular 4π phase slips

Identification of a bulk-edge correspondence linking supercurrent to skyrmion density

Potential experimental signature via nonlinear supercurrent response

Abstract

Due to the structure of the underlying SO(3) $\mathbf d$-vector order parameter, spin triplet superconductors exhibit a bulk-edge correspondence linking the circulation of supercurrent to the bulk magnetic skyrmion density, giving rise to topological hydrodynamics of magnetic skyrmions. To probe the interplay of charge and spin dynamics, we propose a blueprint for a spin-triplet superconducting quantum interference device (SQUID), which functions without a Josephson weak link. The triplet SQUID undergoes nonsingular $4\pi$ phase slips, in which current relaxation is facilitated by spin dynamics that trace out a magnetic skyrmion texture. Inductively coupling the device to a tank circuit and probing the nonlinear supercurrent response via Oersted field measurements could provide an experimental signature of ferromagnetic spin-triplet superconductivity.