Creation of moiré bands in a monolayer semiconductor by spatially periodic dielectric screening

Abstract

Moiré superlattices of two-dimensional van der Waals materials have emerged as a powerful platform for designing electronic band structures and discovering emergent physical phenomena. A key concept involves the creation of long-wavelength periodic potential and moiré bands in a crystal through interlayer hybridization when two materials are overlaid. Here we demonstrate a new approach based on spatially periodic dielectric screening to create moiré bands in a monolayer semiconductor. It relies on reduced dielectric screening of the Coulomb interactions in monolayer semiconductors and their environmental dielectric-dependent electronic band structure. We observe optical transitions between moiré bands in monolayer WSe${}_2$ when it is placed close to small angle-misaligned graphene on hexagonal boron nitride. The moiré bands are a result of long-range Coulomb interactions, strongly gate-tunable, and can have versatile superlattice symmetries independent of the crystal lattice of the host material. Our result also demonstrates that monolayer semiconductors are sensitive local dielectric sensors.

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Cited by in corpus (29)

• Continuous Mott transition in semiconductor moiré superlattices
• Tunable bilayer Hubbard model physics in twisted WSe2
• Tunable superconductivity in electron- and hole-doped Bernal bilayer graphene
• Nanoscale trapping of interlayer excitons in a 2D semiconductor heterostructure
• Nanoscale modification of WS${}_2$ trion emission by its local electromagnetic environment
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• Dielectric catastrophe at the Mott and Wigner transitions in a moiré superlattice
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• Plasmonic polarization sensing of electrostatic superlattice potentials
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• Quantum-phase two-dimensional materials
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