Influence of the effective layer thickness on the groundstate and excitonic properties of transition-metal dichalcogenide systems

Abstract

A self-consistent scheme for the calculations of the interacting groundstate and the near bandgap optical spectra of mono- and multilayer transition-metal-dichalcogenide systems is presented. The approach combines a dielectric model for the Coulomb interaction potential in a multilayer environment, gap equations for the renormalized groundstate, and the Dirac-Wannier-equation to determine the excitonic properties. To account for the extension of the individual monolayers perpendicular to their basic plane, an effective thickness parameter in the Coulomb interaction potential is introduced. Numerical evaluations for the example of MoS${}_2$ show that the resulting finite size effects lead to significant modifications in the optical spectra, reproducing the experimentally observed non hydrogenic features of the excitonic resonance series. Applying the theory for multi-layer configurations, a consistent description of the near bandgap optical properties is obtained all the way from monolayer to bulk. In addition to the well-known in-plane excitons, also interlayer excitons occur in multilayer systems suggesting a reinterpretation of experimental results obtained for bulk material.

15 pages, 12 figures

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Cited by in corpus (5)

• A method to restore the intrinsic dielectric functions of 2D materials in periodic calculations and its applications to the dielectric and optical properties of ultrathin h-BN and MoS2
• Anomalous Stark Shift of Excitonic Complexes in Monolayer Semiconductor
• A colloquium on the variational method applied to excitons in 2D materials
• Dynamical screening effects of substrate phonons on two-dimensional excitons
• Optical Measurement of Pseudo-Spin Texture of the Exciton Fine-Structure in Monolayer WSe2 within the Light Cone