Light-induced coherent magnon excitation in monolayer magnetic nanodots

Abstract

We develop a quantum theory to deal with the coherent magnon excitation in monolayer magnetic nanodots induced by a circularly polarized light. In our theoretical model, the exchange interaction, the magnetic dipole interaction and the light-matter interaction are all taken into account and an effective dynamic equations governing the magnon excitation is derived by a continuum approximation. Our theoretical model shows that the helicity of light and the magnetic dipole interaction govern the magnon excitation and result in the occurrence of various patterns for the spin z-component distribution. We present a scheme to manipulate the single-mode magnon excitation by properly tuning the light frequency.