Magnonic Su-Schrieffer-Heeger model in honeycomb ferromagnets

Abstract

Topological electronics has extended its richness to nonelectronic systems where bosonic quasiparticles can play the role of spin and heat carriers. In particular, topological 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 with tunable relative strength of exchange interactions on different links. Including weak phonon-magnon hybridization does not change the result. Candidate materials are discussed.