Microscopic origin of anomalous interlayer exciton transport in van der Waals heterostructures

Abstract

Van der Waals heterostructures constitute a platform for investigating intriguing many-body quantum phenomena. In particular, transition-metal dichalcogenide (TMD) hetero-bilayers host long-lived interlayer excitons which exhibit permanent out-of-plane dipole moments. Here, we develop a microscopic theory for interlayer exciton-exciton interactions including both the dipolar nature of interlayer excitons as well as their fermionic substructure, which gives rise to an attractive fermionic exchange. We find that these interactions contribute to a drift force resulting in highly non-linear exciton propagation at elevated densities in the MoSe${}_2$-WSe${}_2$ heterostructure. We show that the propagation can be tuned by changing the number of hBN spacers between the TMD layers or by adjusting the dielectric environment. In particular, although counter-intuitive, we reveal that interlayer excitons in free-standing samples propagate slower than excitons in hBN-encapsulated TMDs - due to an enhancement of the net Coulomb-drift with stronger environmental screening. Overall, our work contributes to a better microscopic understanding of the interlayer exciton transport in technologically promising atomically thin semiconductors.

arXiv comment9 pages+8 pages Supplementary Material, 7 figures

References in corpus (34)

• 2D materials and van der Waals heterostructures
• Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides
• Observation of Long-Lived Interlayer Excitons in Monolayer MoSe2-WSe2 Heterostructures
• Computational 2D Materials Database: Electronic Structure of Transition-Metal Dichalcogenides and Oxides
• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Evidence of high-temperature exciton condensation in 2D atomic double layers
• Anomalous Interlayer Exciton Diffusion in Twist-Angle-Dependent Moiré Potentials of WS${}_2$-WSe${}_2$ Heterobilayers
• Exciton diffusion and halo effects in monolayer semiconductors
• Ultrafast transition between exciton phases in van der Waals heterostructures
• Excitons versus electron-hole plasma in monolayer transition metal dichalcogenide semiconductors
• Dipolar interactions between field-tuneable, localized emitters in van der Waals heterostructures
• Analysis of the exciton-exciton interaction in semiconductor quantum wells
• Interlayer coupling in commensurate and incommensurate bilayer structures of transition metal dichalcogenides
• Interlayer exciton dynamics in a dichalcogenide monolayer heterostructure
• Fundamental Limits of Exciton-Exciton Annihilation for Light Emission in Transition Metal Dichalcogenide Monolayers
• Phonon-assisted Photoluminescence from Dark Excitons in Monolayers of Transition Metal Dichalcogenides
• Tunable Phases of Moiré Excitons in van der Waals Heterostructures
• Moiré Potential Impedes Interlayer Exciton Diffusion in van der Waals Heterostructures
• Exciton-exciton interaction in transition-metal dichalcogenide monolayers
• Exciton g-factors of van der Waals heterostructures from first principles calculations
• Excitonic transport driven by repulsive dipolar interaction in a van der Waals heterostructure
• Interlayer excitons in MoSe${}_2$/WSe${}_2$ heterostructures from first-principles
• Quantum diffusion of dipole-oriented indirect excitons in coupled quantum wells
• Exciton-exciton interaction in quantum wells. Optical properties and energy and spin relaxation
• Exciton propagation and halo formation in two-dimensional materials
• Exciton-exciton interaction in transition metal dichalcogenide monolayers and van der Waals heterostructures
• Exciton-Scattering-Induced Dephasing in Two-Dimensional Semiconductors
• Diffusivity Reveals Three Distinct Phases of Interlayer Excitons in MoSe2/WSe2 Heterobilayers
• Negative excitonic diffusion in transition metal dichalcogenides
• Exciton landscape in van der Waals heterostructures
• Excitation-induced transition to indirect band gaps in atomically thin transition metal dichalcogenide semiconductors
• Spin-orbit coupled cold exciton condensates
• Dark exciton-exciton annihilation in monolayer WSe${}_2$
• Nonlinear exciton drift in piezoelectric two-dimensional materials

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• Electrically Controlled Interfacial Charge Transfer Induced Excitons in MoSe2-WSe2 Lateral Heterostructure
• Optical Signatures of Moiré Trapped Biexcitons
• Electrically tunable layer-hybridized trions in doped WSe${}_2$ bilayers
• Two dimensional semiconductors: optical and electronic properties
• Exciton fractional Chern insulators in moiré heterostructures
• A high-$\kappa$ wide-gap layered dielectric for two-dimensional van der Waals heterostructures