Topological magnons in one-dimensional ferromagnetic Su-Schrieffer-Heeger model with anisotropic interaction

TL;DR

This paper explores how anisotropic exchange interactions in a 1D ferromagnetic SSH model lead to topological magnon phases with edge states, revealing rich phase diagrams and potential for magnonic device design.

Contribution

It demonstrates that anisotropic interactions induce topological phases in 1D ferromagnetic magnons, expanding understanding beyond electronic and 2D magnon systems.

Findings

Anisotropic interactions induce topological magnon phases.

Degenerate in-gap edge states localized at chain ends.

Interplay of interactions affects topological phase transitions.

Abstract

Topological magnons in a one-dimensional (1D) ferromagnetic (FM) Su-Schrieffer-Heeger (SSH) model with anisotropic exchange interactions are investigated. Apart from the inter-cellular isotropic Heisenberg interaction, the intercellular anisotropic exchange interactions, i.e. Dzyaloshinskii-Moriya interaction (DMI) and pseudo-dipolar interaction (PDI), also can induce the emergence of the non-trivial phase with two degenerate in-gap edge states separately localized at the two ends of the 1D chain, while the intracellular interactions instead unfavors the topological phase. The interplay among them has synergistic effects on the topological phase transition, very different from that in the two-dimensional (2D) ferromagnet. These results demonstrate that the 1D magnons possess rich topological phase diagrams distinctly different from the electronic version of the SSH model and even the 2D magnons. Due to the lower dimensional structural characteristics of this 1D topological magnonic system, the magnonic crystals can be constructed from bottom to top, which has important potential applications in the design of novel magnonic devices.