Coupling the Higgs mode and ferromagnetic resonance in spin-split superconductors with Rashba spin-orbit coupling

TL;DR

This paper explores how Rashba spin-orbit coupling in superconductors enables the Higgs mode to couple with ferromagnetic resonance, significantly affecting spin susceptibility and enabling detection via inverse spin Hall effect.

Contribution

It demonstrates the linear coupling between the Higgs mode and external exchange fields in spin-split superconductors with Rashba coupling, revealing new ways to detect Higgs modes.

Findings

Enhanced spin susceptibility near critical temperature

Detectable magnon-induced voltage via inverse spin Hall effect

Linear Higgs-spin coupling in Rashba superconductors

Abstract

We consider the Higgs mode at nonzero momentum in superconductors and demonstrate that in the presence of Rashba spin-orbit coupling, it couples linearly with an external exchange field. The Higgs-spin coupling dramatically modifies the spin susceptibility near the superconducting critical temperature and consequently enhances the spin pumping effect in a ferromagnetic insulator/superconductor bilayer system. We show that this effect can be detected by measuring the magnon-induced voltage generated by the inverse spin Hall effect.