Moiré-trapped interlayer trions in a charge-tunable WSe${}_2$/MoSe${}_2$ heterobilayer

Abstract

Transition metal dichalcogenide heterobilayers offer attractive opportunities to realize lattices of interacting bosons with several degrees of freedom. Such heterobilayers can feature moiré patterns that modulate their electronic band structure, leading to spatial confinement of single interlayer excitons (IXs) that act as quantum emitters with $C_3$ symmetry. However, the narrow emission linewidths of the quantum emitters contrast with a broad ensemble IX emission observed in nominally identical heterobilayers, opening a debate regarding the origin of IX emission. Here we report the continuous evolution from a few trapped IXs to an ensemble of IXs with both triplet and singlet spin configurations in a gate-tunable $2H$-MoSe${}_2$/WSe${}_2$ heterobilayer. We observe signatures of dipolar interactions in the IX ensemble regime which, when combined with magneto-optical spectroscopy, reveal that the narrow quantum-dot-like and broad ensemble emission originate from IXs trapped in moiré potentials with the same atomic registry. Finally, electron doping leads to the formation of three different species of localised negative trions with contrasting spin-valley configurations, among which we observe both intervalley and intravalley IX trions with spin-triplet optical transitions. Our results identify the origin of IX emission in MoSe${}_2$/WSe${}_2$ heterobilayers and highlight the important role of exciton-exciton interactions and Fermi-level control in these highly tunable quantum materials.

arXiv comment12 pages, 4 figures

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• Exciton optics, dynamics and transport in atomically thin semiconductors
• Intercell Moiré Exciton Complexes in Electron Lattices
• Optical dipole orientation of interlayer excitons in MoSe${}_2$-WSe${}_2$ heterostacks
• Spatially indirect intervalley excitons in bilayer WSe2
• Superconductivity in the twisted bilayer transition metal dichalcogenide WSe${}_2$ : a quantum cluster study
• Optical signature of cascade transitions between moiré interlayer excitons
• The strong modulation limit of excitons and trions in moiré materials
• Tuning exciton complexes in twisted bilayer WSe2 at intermediate misorientation
• Electromagnetic field assisted exciton diffusion in moiré superlattices
• Microscopic theory of nonlinear phase space filling in polaritonic lattices
• Interplay of trapped species and absence of electron capture in Moiré heterobilayers
• Local Sensing of Correlated Electrons in Dual-moiré Heterostructures using Dipolar Excitons
• Dynamic Valley Polarization in Moire Quantum Dots
• Melting of electronic and excitonic crystals in 2D semiconductor moiré patterns: a perspective from the Lindemann criterion
• Extremely high excitonic $g$-factors in 2D crystals by alloy-induced admixing of band states
• Electrically tunable MoSe${}_2$/WSe${}_2$ heterostructure-based quantum dot
• Quantum siphoning of finely spaced interlayer excitons in reconstructed MoSe2/WSe2 heterostructures
• Trimer superfluidity of antiparallel dipolar excitons in a bilayer heterostructure
• Probing spatially resolved spin density correlations with trapped excitons