Excitonic Magneto-Optical Kerr Effect in 2D Transition Metal Dichalcogenides Induced by Spin Proximity

TL;DR

This paper develops an excitonic theory for the Kerr rotation in 2D transition metal dichalcogenides, revealing how excitonic effects and spin proximity induce significant optical Kerr responses at zero magnetic field.

Contribution

It introduces a comprehensive excitonic model for Kerr rotation in 2D TMDs influenced by spin proximity, highlighting the importance of excitonic effects over single particle approaches.

Findings

Excitonic effects dramatically alter the frequency dependence of optical response.

Excitonic corrections double the optical response in MoS2 near Cobalt.

Finite Kerr angle arises from spin-orbit and exchange interactions without magnetic field.

Abstract

In this paper we develop the excitonic theory of Kerr rotation angle in a two-dimensional (2D) transition metal dichalcogenide at zero magnetic field. The finite Kerr angle is induced by the interplay between spin-orbit splitting and proximity exchange coupling due to the presence of a ferromagnet. We compare the excitonic effect with the single particle theory approach. We show that the excitonic properties of the 2D material lead to a dramatic change in the frequency dependence of the optical response function. We also find that the excitonic corrections enhance the optical response by a factor of two in the case of MoS2 in proximity to a Cobalt thin film.