Discrete Interactions between a few Interlayer Excitons Trapped at a MoSe${}_2$-WSe${}_2$ Heterointerface

Abstract

Interlayer excitons (IXs) in hetero-bilayers of transition metal dichalcogenides (TMDs) represent an exciting emergent class of long-lived dipolar composite bosons in an atomically thin, near-ideal two-dimensional (2D) system. The long-range interactions that arise from the spatial separation of electrons and holes can give rise to novel quantum, as well as classical multi-particle correlation effects. In order to acquire a detailed understanding of the possible many-body effects, the fundamental interactions between individual IXs have to be studied. Here, we trap a tunable number of dipolar within a nanoscale confinement potential induced by placing a MoSe${}_2$-WSe${}_2$ hetero-bilayer (HBL) onto an array of SiO${}_2$ nanopillars. We control the mean occupation of the IX trap via the optical excitation level and observe discrete sharp-line emission from different configurations of interacting IXs. We identify these features as different multiparticle states with $N_{IX}\sim 1-5$ via their power dependencies and directly measure the hierarchy of dipolar and exchange interactions as $N_{IX}$ increases. The interlayer biexciton ($N_{IX}=2$) is found to be an emission doublet that is blue-shifted from the single exciton by $\Delta E=(8.4\pm 0.6)$ meV and split by $2J=(1.2\pm 0.5)$ meV. The blueshift is even more pronounced for triexcitons ($(12.4\pm 0.4)$ meV), quadexcitons ($(15.5\pm 0.6)$ meV) and quintexcitons ($(18.2\pm 0.8)$ meV). These values are shown to be mutually consistent with numerical modelling of dipolar excitons confined to a harmonic trapping potential having a confinement lengthscale in the range $\ell \approx 3$ nm. Our results contribute to the understanding of interactions between IXs in TMD HBLs at the discrete limit of only a few excitations and represent a key step towards exploring quantum correlations between them.

15 pages, 3 figures plus Supplementary Information (19 pages, 11 pages)

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Cited by in corpus (33)

• Raman spectrum of Janus transition metal dichalcogenide monolayers WSSe and MoSSe
• Nanoscale trapping of interlayer excitons in a 2D semiconductor heterostructure
• Moiré-trapped interlayer trions in a charge-tunable WSe${}_2$/MoSe${}_2$ heterobilayer
• Optical read-out of Coulomb staircases in a moiré superlattice via trapped interlayer trions
• Optical control of valley Zeeman effect through many-exciton interactions
• Emergence of highly linearly polarized interlayer exciton emission in MoSe${}_2$/WSe${}_2$ heterobilayers with transfer-induced layer corrugation
• Lasing of Moiré Trapped MoSe${}_2$/WSe${}_2$ Interlayer Excitons Coupled to a Nanocavity
• Flipping exciton angular momentum with chiral phonons in MoSe${}_2$/WSe${}_2$ heterobilayers
• Highly Tunable Ground and Excited State Excitonic Dipoles in Multilayer 2H-MoSe${}_2$
• Optical signature of cascade transitions between moiré interlayer excitons
• Extrinsic localized excitons in patterned 2D semiconductors
• Tuning the Optical Properties of an MoSe${}_2$ Monolayer Using Nanoscale Plasmonic Antennas
• Twist angle dependent interlayer transfer of valley polarization from excitons to free charge carriers in WSe${}_2$/MoSe${}_2$ heterobilayers
• Luminescence anomaly of dipolar valley excitons in homobilayer semiconductor moiré superlattices
• Harmonic to anharmonic tuning of moiré potential leading to unconventional Stark effect and giant dipolar repulsion in WS${}_2$/WSe${}_2$ heterobilayer
• Crystal Phases of Charged Interlayer Excitons in van der Waals Heterostructures
• Interlayer donor-acceptor pair excitons in MoSe2/WSe2 moiré heterobilayer
• Controlled Interlayer Exciton Ionization in an Electrostatic Trap in Atomically Thin Heterostructures
• Optical Signatures of Moiré Trapped Biexcitons
• Quadrupolar and dipolar excitons in symmetric trilayer heterostructures: Insights from first principles theory
• Microscopic theory of polariton-polariton interactions
• Single exciton trapping in an electrostatically defined 2D semiconductor quantum dot
• Microscopic theory of nonlinear phase space filling in polaritonic lattices
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• Trapping Interlayer Excitons in van der Waals Heterostructures by Potential Arrays
• Two dimensional semiconductors: optical and electronic properties
• Dipolar interactions enhanced by two-dimensional dielectric screening in few-layer van der Waals structures
• Twistronics and moiré superlattice physics in 2D transition metal dichalcogenides
• Spin-orbit coupled depairing of a dipolar biexciton superfluid
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• Charged bosons made of fermions in a solid state system without Cooper pairing
• Long-range spatial extension of exciton states in van der Waals heterostructure
• Effective long-range attraction of moiré excitons under the influence of atomic reconstructions and anisotropic screening