Retrieval of material properties of monolayer transition-metal dichalcogenides from magnetoexciton energy spectra

Abstract

Reduced exciton mass, polarizability, and dielectric constant of the surrounding medium are essential properties for semiconducting materials, and they have been extracted recently from the magnetoexciton energies. However, the acceptable accuracy of the suggested method requires very high magnetic intensity. Therefore, in the present paper, we propose an alternative method of extracting these material properties from recently available experimental magnetoexciton s-state energies in monolayer transition-metal dichalcogenides (TMDCs). The method is based on the high sensitivity of exciton energies to the material parameters in the Rytova-Keldysh model. It allows us to vary the considered material parameters to get the best fit of the theoretical calculation to the experimental exciton energies for the $1s$, $2s$, and $3s$ states. This procedure gives values of the exciton reduced mass and $2D$ polarizability. Then, the experimental magnetoexciton spectra compared to the theoretical calculation also determine the average dielectric constant. Concrete applications are presented only for monolayers WSe${}_2$ and WS${}_2$ from the recently available experimental data; however, the presented approach is universal and can be applied to other monolayer TMDCs. The mentioned fitting procedure requires a fast and effective method of solving the Schrödinger equation of an exciton in monolayer TMDCs with a magnetic field. Therefore, we also develop such a method in this paper for highly accurate magnetoexciton energies.

10 pages, 5 figures, 4 tables; submitted to Phys. Rev. B

References in corpus (10)

• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Determination of band alignment in the single layer MoS2/WSe2 heterojunction
• Mono- and Bilayer WS2 Light-Emitting Transistors
• Probing the influence of dielectric environment on excitons in monolayer WSe2: Insight from high magnetic fields
• Colloquium: Graphene spectroscopy
• Excitonic valley effects in monolayer WS${}_2$ under high magnetic fields
• Magneto-photoluminescence of exciton Rydberg states in monolayer WSe${}_2$
• Luminescent emission of excited Rydberg excitons from monolayer WSe2
• Nonlinear optical selection rules of excitons in monolayer transition metal dichalcogenides
• Enhanced Magnetism in Heterostructures with Transition-Metal Dichalcogenide Monolayers