Effect of strong Dzyaloshinskii–Moriya interaction on magnon–phonon coupling and magnon band topology

Determine how strong Dzyaloshinskii–Moriya interaction modifies the established collinear-magnet picture in two-dimensional magnetic systems, in which Heisenberg exchange combined with out-of-plane Dzyaloshinskii–Moriya interaction (parallel to the spin direction) induces magnon–phonon coupling with higher-order bosonic interactions and in-plane Dzyaloshinskii–Moriya interaction (perpendicular to the spins) primarily alters magnon band topology; specifically, ascertain the modifications introduced by strong Dzyaloshinskii–Moriya interaction beyond collinear magnetic ground states.

Background

Prior theoretical and experimental studies have largely focused on topological magnons in systems with weak Dzyaloshinskii–Moriya interaction (DMI) and often assume collinear magnetic ground states. In that regime, the combination of Heisenberg exchange with out-of-plane DMI (aligned with the spin direction) leads to magnon–phonon coupling that introduces higher-order bosonic interactions beyond linear spin-wave theory, whereas in-plane DMI (perpendicular to the spins) mainly affects magnon band topology.

The paper emphasizes that systematic exploration of the strong-DMI regime is lacking and raises the question of how strong DMI alters the above understanding, particularly when noncollinear or noncoplanar magnetic textures may be stabilized. The authors’ model and analysis address aspects of this question, but the statement frames it as an explicit open question motivating broader investigation across two-dimensional magnetic systems.