Confined-state physics and signs of fermionization of moiré excitons in WSe${}_2$/MoSe${}_2$ heterobilayers

Abstract

We revisit and extend the standard bosonic interpretation of interlayer excitons in the moiré potential of twisted heterostructures of transition-metal dichalcogenides. In our experiments, we probe a high quality MoSe${}_2$/WSe${}_2$ van der Waals bilayer heterostructure via density-dependent photoluminescence spectroscopy and reveal strongly developed, unconventional spectral shifts of the emergent moiré exciton resonances. The observation of saturating blueshifts of successive exciton resonances allow us to explain their physics in terms of a model utilizing fermionic saturable absorbers. This approach is strongly inspired by established quantum-dot models, which underlines the close analogy of interlayer excitons trapped in pockets of the moiré potential, and quantum emitters with discrete eigenstates.

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Cited by in corpus (7)

• Exciton-exciton interactions in van der Waals heterobilayers
• Exciton-phonon-scattering: A competition between bosonic and fermionic nature of bound electron-hole pairs
• Harmonic to anharmonic tuning of moiré potential leading to unconventional Stark effect and giant dipolar repulsion in WS${}_2$/WSe${}_2$ heterobilayer
• Non-bosonic moiré excitons
• Fermionic vs. bosonic thermalization in the phonon-driven exciton dynamics: An analytic dimensionality study
• Theory of phonon sidebands in the absorption spectra of moiré exciton-polaritons
• Effective long-range attraction of moiré excitons under the influence of atomic reconstructions and anisotropic screening