Intercell Moiré Exciton Complexes in Electron Lattices

Abstract

Excitons, Coulomb-bound electron-hole pairs, play a fundamental role in both optical excitation and correlated phenomena in solids. When an exciton interacts with other quasi-particles, few- and many-body excited states, such as trions, exciton Fermi-polarons, Mahan excitons can appear. Here, we report a new interaction between exciton and charges enabled by unusual quantum confinement in 2D moiré superlattices, which results in novel exciton many-body ground states composed of moiré excitons and correlated electron lattices. Unique to H-stacked (or 60o-twisted) WS2/WSe2 heterobilayer, we found that the interlayer atomic registry and moiré structural reconstruction leads to an interlayer moiré exciton (IME) whose hole in one layer is surrounded by its partner electron's wavefunction spread among three adjacent moiré traps in the other layer. This 3D excitonic structure can enable large in-plane electrical quadrupole moments in addition to the vertical dipole. Upon doping, the electric quadrupole facilitates the binding of IME to the charges in neighboring moiré cells, forming an intercell charged exciton complex. The exciton complex is unveiled by the IME photoluminescence energy jumps when the electron lattices form at both fractional and integer-filled moiré minibands, with replica-like spectral features between successive integer moiré fillings. Our work provides the framework in understanding and engineering emergent exciton many-body states in correlated moiré charge orders.

References in corpus (12)

• Observation of Long-Lived Interlayer Excitons in Monolayer MoSe2-WSe2 Heterostructures
• Observation of Moiré Excitons in WSe2/WS2 Heterostructure Superlattices
• Resonantly hybridised excitons in moiré superlattices in van der Waals heterostructures
• Moiré excitons: from programmable quantum emitter arrays to spin-orbit coupled artificial lattices
• Moiré heterostructures as a condensed matter quantum simulator
• Quantum anomalous Hall effect from intertwined moiré bands
• Magic in twisted transition metal dichalcogenide bilayers
• Quantum Criticality in Twisted Transition Metal Dichalcogenides
• Spin liquid phase of the $S=\frac{1}{2}$ $J_1-J_2$ Heisenberg model on the triangular lattice
• Directional Interlayer Spin-Valley Transfer in Two-Dimensional Heterostructures
• Hartree-Fock study of the moiré Hubbard model for twisted bilayer transition metal dichalcogenides
• Competing magnetic states in transition metal dichalcogenide moiré materials

Cited by in corpus (12)

• Programming Correlated Magnetic States via Gate Controlled Moiré Geometry
• Quadrupolar Excitons and Hybridized Interlayer Mott Insulator in a Trilayer Moiré Superlattice
• Excitons and trions in monolayer semiconductors with correlated electrons
• Superradiance of Strongly Interacting Dipolar Excitons in Moiré Quantum Materials
• Strong Correlation Driven Quadrupolar to Dipolar Exciton Transitions in a Trilayer Moiré Superlattice
• Energy shifts and broadening of excitonic resonances in electrostatically-doped semiconductors
• Purely electronic model for exciton-polaron formation in moiré heterostructures
• Moiré excitons in generalized Wigner crystals
• Optical signatures of -1/3 fractional quantum anomalous Hall state in twisted MoTe2
• Magnetic and nematic order of Bose-Fermi mixtures in moiré superlattices of 2D semiconductors
• Exciton-Anyon Binding in Fractional Chern Insulators: Spectral Fingerprints
• Origin of Moiré Potentials in WS${}_2$/WSe${}_2$ Heterobilayers: Contributions from Lattice Reconstruction and Interlayer Charge Transfer