Moiré lattice-induced formation and tuning of hybrid dipolar excitons in twisted WS${}_2$/MoSe${}_2$ heterobilayers

Abstract

Moiré superlattices formed in van der Waals bilayers have enabled the creation and manipulation of new quantum states, as is exemplified by the discovery of superconducting and correlated insulating states in twisted bilayer graphene near the magic angle. Twisted bilayer semiconductors may lead to tunable exciton lattices and topological states, yet signatures of moiré excitons have been reported only in closely angularly-aligned bilayers. Here we report tuning of moiré lattice in WS${}_2$ /MoSe${}_2$ bilayers over a wide range of twist angles, leading to the continuous tuning of moiré lattice induced interlayer excitons and their hybridization with optically bright intralayer excitons. A pronounced revival of the hybrid excitons takes place near commensurate twist angles, 21.8°and 38.2°, due to interlayer tunneling between states connected by a moiré reciprocal lattice vector. From the angle dependence, we obtain the effective mass of the interlayer excitons and the electron inter-layer tunneling strength. These findings pave the way for understanding and engineering rich moiré-lattice induced phenomena in angle-twisted semiconductor van dar Waals heterostructures.

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Cited by in corpus (5)

• Theory of moiré localized excitons in transition-metal dichalcogenide heterobilayers
• Moiré induced topology and flat bands in twisted bilayer WSe${}_2$: A first-principles study
• Topological phases in N-layer ABC-graphene boron-nitride moire superlattices
• Spatially mixed moiré excitons in two-dimensional van der Waals superlattices
• Exciton Transport under Periodic Potential in MoSe2/WSe2 Heterostructures