Fine structure of $\mathrm{K}$-excitons in multilayers of transition metal dichalcogenides

TL;DR

This study investigates the fine structure of K-excitons in multilayer MoS2, revealing how interlayer coupling influences excitonic properties through combined experimental and theoretical approaches.

Contribution

It provides a detailed analysis of excitonic resonances in multilayer MoS2, highlighting the effects of interlayer coupling and symmetry on exciton properties, with experimental magneto-optical validation.

Findings

Hybridization of Bloch states causes additional excitonic resonances.

Magneto-optical measurements distinguish inter- and intralayer excitons.

Spin-orbit interaction parameters are estimated for bi- and trilayer MoS2.

Abstract

Reflectance and magneto-reflectance experiments together with theoretical modelling based on the $\mathbf{k\cdot p}$ approach have been employed to study the evolution of direct bandgap excitons in MoS$_2$ layers with a thickness ranging from mono- to trilayer. The extra excitonic resonances observed in MoS$_2$ multilayers emerge as a result of the hybridization of Bloch states of each sub-layer due to the interlayer coupling. The properties of such excitons in bi- and trilayers are classified by the symmetry of corresponding crystals. The inter- and intralayer character of the reported excitonic resonances is fingerprinted with the magneto-optical measurements: the excitonic $g$-factors of opposite sign and of different amplitude are revealed for these two types of resonances. The parameters describing the strength of the spin-orbit interaction are estimated for bi- and trilayer MoS$_2$.