Spin-wave flat bands in antiferromagnetic magnonic crystals
Phys. Rev. B 114, 084428 – Published 27 August, 2026
DOI: https://doi.org/10.1103/51y8-xbnt
Abstract
Tuning the propagation characteristics of spin waves (or magnons) is a central task in antiferromagnetic magnonics. Here, we theoretically investigate the spin-wave flat band (FB) behavior in antiferromagnetic magnonic crystals formed by a periodic Dzyaloshinskii-Moriya interaction (DMI). The conditions required for the emergence of magnon FBs are identified. In addition, we find that these FBs essentially describe a series of magnon standing-wave modes localized in regions of high DMI. Notably, an external magnetic field can lift the degeneracy of magnon polarization, leading to a few purely left- and right-handed magnon FBs. Micromagnetic simulations confirm the theoretical predictions with good agreement. Our work offers a simple method to obtain localized magnons with pure polarization in antiferromagnets, which may facilitate the design of diverse functional magnonic devices by harnessing the magnon polarization degree of freedom.
