Magnetization dynamics and Majorana fermions in ferromagnetic Josephson junctions along the quantum spin Hall edge

TL;DR

This paper explores the unique magnetization dynamics and Majorana fermions in ferromagnetic Josephson junctions along quantum spin Hall edges, revealing novel phenomena due to topological effects.

Contribution

It introduces a combined analytical and numerical study of ferromagnetic Josephson junctions on quantum spin Hall edges, highlighting unusual current-phase relations and Majorana fermion localization.

Findings

Anomalous current-phase relation induces supercurrent-driven magnetization dynamics.

Majorana fermions are spatially localized at the junction.

Topological effects lead to phenomena absent in non-topological systems.

Abstract

We investigate the interplay between ferromagnetic and superconducting order at the edge of a quantum spin Hall insulator. Using complementary analytical and self-consistent numerical approaches, we study a ferromagnetic Josephson junction and show how the direct coupling between magnetism and the superconducting U(1) phase gives rise to several unusual phenomena which distinguishes the present system from its non-topological equivalent. In particular, we demonstrate how the anomalous current-phase relation triggers supercurrent-induced magnetization dynamics and also study the spatial localization of the Majorana fermions appearing in the junction.