Topological phases of electrons induced by electron-magnon interactions

TL;DR

This paper demonstrates that electron-magnon interactions can induce topological phases in electron systems without the need for strong spin-orbit coupling or magnetic fields, by transferring symmetry-breaking effects from the spin system.

Contribution

It introduces a novel 'topology transfer' mechanism where electron-magnon interactions create topological phases in otherwise trivial electron systems.

Findings

Realization of quantum Hall and quantum spin Hall phases via electron-magnon coupling

Topological phases achieved without strong spin-orbit coupling or external magnetic fields

Demonstration of topology transfer in simple ferromagnetic spin systems

Abstract

Topological phases of electrons such as topological insulators and quantum Hall states typically require strong spin-orbit coupling or magnetic fields. In this study, we consider an electron system coupled to a spin system, where electrons interact with magnons, quasiparticles of spin waves. We show that the interaction between electrons and magnons transfers the effect of symmetry breaking in the spin system to the electron system, whereby a non-trivial topological phase can be induced in the electron system that is otherwise topologically trivial. Through this ``topology transfer'' mechanism, we demonstrate the realization of various topological phases, including quantum Hall and quantum spin Hall insulators, in simple ferromagnetic spin systems, without requiring strong spin-orbit coupling or external magnetic field for electron systems.