Graphene-like Topological Magnonic Crystal

Spin waves in 2D magnets can exhibit properties similar to electrons in 2D materials, for example linear-dispersion Dirac cones [1]. However, these spin wave states appear at high frequencies and small scales at which experimental probes, tunability, and applications are limited. Here we demonstrate that it is possible to realize similar physics in magnonic crystals patterned in yttrium-iron garnet. The design of spin wave states in these materials can be guided by the analogy to 2D graphene-like materials. In particular, the magnonic crystal can be made to host 1-D localized edge states of topological origin and a few other interesting features in the few-GHz frequency range. This work demonstrates that it is possible to engineer the behavior of spin waves at the micron scale by learning lessons from quantum materials at the nano-scale.

[1] J. Schneeloch et. al., npj Quantum Mater. 7, 66 (2022).