Magnonic Su-Schrieffer-Heeger Model in Honeycomb Ferromagnets

TL;DR

This paper introduces a magnonic analog of the Su-Schrieffer-Heeger model in honeycomb ferromagnets, showing how exchange interactions and Dzyaloshinskii-Moriya interaction influence topological magnon phases and edge states.

Contribution

It demonstrates that alternating exchange interactions, combined with DMI, can realize topological magnon phases in honeycomb ferromagnets, expanding topological electronics to magnonic systems.

Findings

Identification of a magnonic SSH model in honeycomb ferromagnets

Calculation of topological phase diagram and edge states

Analysis of magnon Hall effect and hybridization effects

Abstract

Topological electronics has extended its richness to non-electronic systems where phonons and magnons can play the role of electrons. In particular, topological phases of magnons can be enabled by the Dzyaloshinskii-Moriya interaction (DMI) which acts as an effective spin-orbit coupling. We show that besides DMI, an alternating arrangement of Heisenberg exchange interactions critically determines the magnon band topology, realizing a magnonic analog of the Su-Schrieffer-Heeger model. On a honeycomb ferromagnet with perpendicular anisotropy, we calculate the topological phase diagram, the chiral edge states, and the associated magnon Hall effect by allowing the relative strength of exchange interactions on different links to be tunable. Including weak phonon-magnon hybridization does not change the result. Candidate materials are discussed.