Magnon-Phonon Coupling in Twisted 2D van der Waals Magnets*

Since the moiré superlattice was discovered in a graphene system, the new rise of the twistronics greatly expanding the application prospects of 2D materials. In heterostructures and homostructures formed by 2D atomic crystals, the stacking configuration of adjacent layers are strongly correlated to the physical properties of the van der Waals materials[1], bringing various novel phenomena such as unconventional superconductivity. Recently, it has been shown that the magnetic properties of 2D magnets can be controlled by the twist angle of magnetic moiré superlattices[2]. The effect of twist angel and local interlayer exchange coupling on the formation of domains has been reported in the literature[3]. According to some recent experimental works, we find that magnons may be strongly coupled to phonons at certain twist angles. So here, we propose a modified theoretical model based on the existing theories[4] to study the behavior of magnons in twisted 2D van der Waals magnets system. We introduce a term related to the action of phonons in the equation and improve the approximation method used for solving the equation. Our work is an enrichment of the magnetic dynamics in twisted 2D van der Waals magnets system.

Corresponding email: zhang@tongji.edu.cn