Spin waves in the bilayer van der Waals magnet CrSBr

TL;DR

This paper derives analytical formulas for spin wave frequencies in monolayer and bilayer CrSBr, showing their tunability by magnetic fields across different magnetic phases.

Contribution

It provides a comprehensive analytical framework for understanding spin wave behavior in CrSBr, including effects of various interactions and phases.

Findings

Spin wave frequencies are tunable by in-plane magnetic fields.

Analytical expressions cover antiferromagnetic, ferromagnetic, and canted phases.

Roles of exchange interactions, anisotropy, and dipolar fields are elucidated.

Abstract

We derive analytical expressions for the spin wave frequencies and precession amplitudes in monolayer and antiferromagnetically coupled bilayer CrSBr under in-plane external magnetic fields. The analysis covers the antiferromagnetic, ferromagnetic, and canted phases, demonstrating that the spin wave frequencies in all phases are tunable by the applied magnetic field. We discuss the roles of intra- and interlayer exchange interactions, triaxial anisotropy, and intralayer dynamic dipolar fields in controlling the magnetization dynamics.