Polarization and charge-separation of moiré excitons in van der Waals heterostructures

Abstract

Twisted transition metal dichalcogenide (TMD) bilayers exhibit periodic moiré potentials, which can trap excitons at certain high-symmetry sites. At small twist angles, TMD lattices undergo an atomic reconstruction, altering the moiré potential landscape via the formation of large domains, potentially separating the charges in-plane and leading to the formation of intralayer charge-transfer (CT) excitons. Here, we employ a microscopic, material-specific theory to investigate the intralayer charge-separation in atomically reconstructed MoSe${}_2$-WSe${}_2$ heterostructures. We identify three distinct and twist-angle-dependent exciton regimes including localized Wannier-like excitons, polarized excitons, and intralayer CT excitons. We calculate the moiré site hopping for these excitons and predict a fundamentally different twist-angle-dependence compared to regular Wannier excitons - presenting an experimentally accessible key signature for the emergence of intralayer CT excitons. Furthermore, we show that the charge separation and its impact on the hopping can be efficiently tuned via dielectric engineering.

arXiv comment6 pages, 5 figures

References in corpus (38)

• Van der Waals heterostructures
• Observation of Long-Lived Interlayer Excitons in Monolayer MoSe2-WSe2 Heterostructures
• Moiré Excitons in Van der Waals Heterostructures
• Signatures of moiré-trapped valley excitons in MoSe${}_2$/WSe${}_2$ heterobilayers
• Exciton physics and device application of two-dimensional transition metal dichalcogenide semiconductors
• Moiré excitons: from programmable quantum emitter arrays to spin-orbit coupled artificial lattices
• Atomic reconstruction in twisted bilayers of transition metal dichalcogenides
• Tight-binding model and direct-gap/indirect-gap transition in single-layer and multi-layer MoS${}_2$
• Long-lived direct and indirect interlayer excitons in van der Waals heterostructures
• Relaxation and Domain Formation in Incommensurate 2D Heterostructures
• Atomic reconstruction and moiré patterns in transition metal dichalcogenide van der Waals heterostructures
• Momentum-space indirect interlayer excitons in transition metal dichalcogenide van der Waals heterostructures
• Imaging moiré flat bands in 3D reconstructed WSe2/WS2 superlattices
• Stacking domains and dislocation networks in marginally twisted bilayers of transition metal dichalcogenides
• Interlayer coupling in commensurate and incommensurate bilayer structures of transition metal dichalcogenides
• Broken mirror symmetry in excitonic response of reconstructed domains in twisted MoSe${}_2$/MoSe${}_2$ bilayers
• Moiré Excitons Correlated with Superlattice Structure in Twisted WSe${}_2$/WSe${}_2$ Homobilayers
• Tunable Phases of Moiré Excitons in van der Waals Heterostructures
• Excitons in mesoscopically reconstructed moiré heterostructures
• Moiré excitons in MoSe${}_2$-WSe${}_2$ heterobilayers and heterotrilayers
• Impact of strain on the excitonic linewidth in transition metal dichalcogenides
• Piezoelectricity and valley Chern number in inhomogeneous hexagonal 2D crystals
• Rotational and Dilational Reconstruction in Transition Metal Dichalcogenide Moiré Bilayers
• Piezoelectric networks and ferroelectric moiré superlattice domains in twistronic WS${}_2$/MoS${}_2$ and WSe${}_2$/MoSe${}_2$ bilayers
• Moiré-Bose-Hubbard model for interlayer excitons in twisted transition metal dichalcogenide heterostructures
• Exciton landscape in van der Waals heterostructures
• Dielectric catastrophe at the Mott and Wigner transitions in a moiré superlattice
• Electrical tuning of moiré excitons in MoSe${}_2$ bilayers
• Interferences of electrostatic moiré potentials and bichromatic superlattices of electrons and excitons in transition metal dichalcogenides
• Band energy landscapes in twisted homobilayers of transition metal dichalcogenides
• Practical Sparse Matrices in C++ with Hybrid Storage and Template-Based Expression Optimisation
• Relaxation effects in twisted bilayer molybdenum disulfide: structure, stability, and electronic properties
• Spatially indirect intervalley excitons in bilayer WSe2
• Bosonic Delocalization of Dipolar Moiré Excitons
• Self-organised quantum dots in marginally twisted MoSe${}_2$/WSe${}_2$ and MoS${}_2$/WS${}_2$ bilayers
• Lattice reconstruction in MoSe${}_2$-WSe${}_2$ heterobilayers synthesized by chemical vapor deposition
• Impact of atomic reconstruction on optical spectra of twisted TMD homobilayers
• Optical Signatures of Moiré Trapped Biexcitons