Stacking Domain Wall Magnons in Twisted van der Waals Magnets

TL;DR

This paper demonstrates that stacking domain walls in twisted van der Waals magnets like bilayer CrI3 can host stable, low-energy 1D magnon channels, revealing new magnetic dynamics and potential for stacking engineering.

Contribution

It introduces the concept of stacking domain walls hosting magnon channels in twisted van der Waals magnets, expanding the understanding of magnetic properties and dynamics.

Findings

Stacking domain walls host lower-energy 1D magnon channels.

Some magnon channels are hidden in homogeneous backgrounds.

Moiré superlattices realize interconnected magnon networks.

Abstract

Using bilayer CrI$_3$ as an example, we demonstrate that stacking domain walls in van der Waals magnets can host one dimensional (1D) magnon channels, which have lower energies than bulk magnons. Interestingly, some magnon channels are hidden in magnetically homogeneous background and can only be inferred with the knowledge of stacking domain walls. Compared to 1D magnons confined in magnetic domain walls, 1D magnons in stacking domain walls are more stable against external perturbations. We show that the relaxed moir\'e superlattices of small-angle twisted bilayer CrI$_3$ is a natural realization of stacking domain walls and host interconnected moir\'e magnon network. Our work reveals the importance of stacking domain walls in understanding magnetic properties of van der Waals magnets, and extends the scope of stacking engineering to magnetic dynamics.