Non-Generic Dispersion of Excitons in the Bulk of WSe${}_2$

Abstract

We combine electron energy-loss spectroscopy (EELS) and density functional theory (DFT) calculations to study the dispersion and effective mass of excitons in the bulk of WSe${}_2$. Our EELS data suggest substantial deviations from the generic quadratic momentum dependence along the $\Gamma K$-direction. From the DFT-derived Kohn-Sham states we deduce the EELS response without the inclusion of particle-hole attraction to study the possible role of the single-particle band structure on the exciton behavior. Based on this analysis we argue in favor of a strongly momentum dependent particle-hole interaction in WSe${}_2$ and other group VI-transition-metal dichalcogenides.

References in corpus (4)

• Electronic properties of single-layer and multilayer transition metal dichalcogenides $M{X}_2$ ($M=$ Mo, W and $X=$ S, Se)
• Exciton band structure in two-dimensional materials
• Electron Energy-Loss Spectroscopy: A versatile tool for the investigations of plasmonic excitations
• Investigation of the dispersion and the effective masses of excitons in bulk 2H-MoS2 using transition electron energy-loss spectroscopy

Cited by in corpus (5)

• Momentum-Resolved View of Electron-Phonon Coupling in Multilayer WSe${}_2$
• Semiconductor-to-Metal Transition in the Bulk of WSe2 upon Potassium Intercalation
• Excitons in epitaxially grown WS2 on Graphene: a nanometer-resolved EELS and DFT study
• Dimensionality-Dependent Exciton Dispersion in a Single-Band Mott Insulator
• Excited-state band structure mapping