Twisted surface magnons induced by magnon spin-orbit coupling
Phys. Rev. B 112, 094441 – Published 22 September, 2025
DOI: https://doi.org/10.1103/dyd7-vp2j
Abstract
Magnon spin-orbit coupling (MSOC) has been studied intensively, leading to the findings of a variety of exotic phenomena such as magnon Hall effect and magnon spin Nernst effect. Here we report a new magnon state induced by the MSOC caused by the dipolar interaction, namely, the twisted magnetostatic surface magnons in antiferromagnetic (AFM) and ferromagnetic (FM) cylindrical tubes. We find that magnons lacking orbital angular momentum (OAM) exclusively manifest as bulk modes, while introducing OAM leads to emergence of additional surface magnon modes. In the AFM tube, two twisted surface magnon modes appear—one is localized on the outer surface and another is confined to the inner surface. Both modes show spin-OAM locking propagating characteristics. In the FM tube, only one twisted surface magnon emerges, located on the outer or inner surface depending on the direction of OAM. These characteristics are explained based on the MSOC effect. Micromagnetic simulations verify the theoretical predictions. The polarization-selective propagation of twisted surface magnons, governed by spin-OAM locking, may provide a basis for designing novel magnonic devices.
