Exciton-exciton interaction in transition-metal dichalcogenide monolayers

Abstract

We study theoretically the Coulomb interaction between excitons in transition metal dichalcogenide (TMD) monolayers. We calculate direct and exchange interaction for both ground and excited states of excitons. The screening of the Coulomb interaction, specific to monolayer structures, leads to the unique behavior of the exciton-exciton scattering for excited states, characterized by the non-monotonic dependence of the interaction as function of the transferred momentum. We find that the nontrivial screening enables the description of TMD exciton interaction strength by approximate formula which includes exciton binding parameters. The influence of screening and dielectric environment on the exciton-exciton interaction was studied, showing qualitatively different behavior for ground state and excited states of excitons. Furthermore, we consider exciton-electron interaction, which for the excited states is governed by the dominant attractive contribution of the exchange component, which increases with the excitation number. The results provide a quantitative description of the exciton-exciton and exciton-electron scattering in transition metal dichalcogenides, and are of interest for the design of perspective nonlinear optical devices based on TMD monolayers.

10 pages, 6 figures

References in corpus (11)

• 2D materials and van der Waals heterostructures
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• Many-body effects in nonlinear optical responses of 2D layered semiconductors
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Cited by in corpus (7)

• Atomically thin mirrors made of monolayer semiconductors
• Exciton optics, dynamics and transport in atomically thin semiconductors
• Microscopic origin of anomalous interlayer exciton transport in van der Waals heterostructures
• A colloquium on the variational method applied to excitons in 2D materials
• Enhanced nonlinear interaction of polaritons via excitonic Rydberg states in monolayer WSe2
• Optical Signatures of Moiré Trapped Biexcitons
• Modelling excitonic Mott transitions in two-dimensional semiconductors