Two-Dimensional Twisted Ferromagnetic Domain Wall as a Spin-Wave Diffraction Grating

TL;DR

This paper theoretically investigates how twisted ferromagnetic domain walls in 2D materials can act as diffraction gratings for spin waves, revealing complex dynamics and potential for magnonic device applications.

Contribution

It introduces the concept of a spin-wave diffraction grating created by a twisted domain wall in a 2D ferromagnet with anisotropy, combining gauge field effects and periodicity.

Findings

Twisted domain walls generate effective gauge fields for spin waves.

Periodic modulation of the Hamiltonian causes multiple diffracted spin wave modes.

The study reveals complex spin-wave dynamics and potential magnonic applications.

Abstract

We present a theoretical study of spin-wave scattering by a twisted domain wall (DW) in a two-dimensional ferromagnet with easy-axis anisotropy. While the twisted DW generates an effective gauge field for spin waves, leading to a deflection of their trajectories, our main focus is on a distinct effect that arises when a hard-axis anisotropy is present in addition to the easy-axis anisotropy. In this case, the translational symmetry of the spin-wave Hamiltonian along the DW is broken, resulting in a periodic modulation of the Hamiltonian. This periodicity leads to the formation of multiple diffracted spin wave modes on both sides of the DW, engendering a DW-induced magnonic diffraction pattern. The interplay between the emergent gauge field and the anisotropy-induced periodicity reveals rich spin-wave dynamics and suggests potential applications for manipulating magnon flow in two-dimensional magnetic textures.