Large-scale mapping of moiré superlattices by Raman imaging of interlayer breathing mode and moiré phonons

Abstract

Moiré superlattices can induce correlated-electronic phases in twisted van-der-Waals materials. Strongly correlated quantum phenomena emerge, such as superconductivity and the Mott-insulating state. However, moiré superlattices produced through artificial stacking can be quite inhomogeneous, which hampers the development of a clear correlation between the moiré period and the emerging electrical and optical properties. Here we demonstrate in twisted-bilayer transition-metal dichalcogenides that low-frequency Raman scattering can be utilized not only to detect atomic reconstruction, but also to map out the inhomogeneity of the moiré lattice over large areas. The method is established based on the finding that both the interlayer-breathing mode and moiré phonons are highly susceptible to the moiré period and provide characteristic fingerprints. We visualize microscopic domains with an effective twist-angle resolution of ~0.1°. This ambient non-invasive methodology can be conveniently implemented to characterize and preselect high-quality areas of samples for subsequent device fabrication, and for transport and optical experiments.

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• Photonic crystals for nano-light in moiré graphene superlattices
• Observation of interlayer phonon modes in van der Waals heterostructures
• Raman spectroscopy of the interlayer shear mode in few-layer MoS2 flakes
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• Lattice dynamics localization in low-angle twisted bilayer graphene

Cited by in corpus (11)

• Large-scale mapping of moiré superlattices by Raman imaging of interlayer breathing mode and moiré phonons
• Observation of flat $\Gamma$ moiré bands in twisted bilayer WSe${}_2$
• Determining the Twist Angle of Bilayer Graphene by Machine Learning Analysis of its Raman Spectrum
• Stacking-Dependent Optical Properties in Bilayer WSe2
• Optical dipole orientation of interlayer excitons in MoSe${}_2$-WSe${}_2$ heterostacks
• Chiral valley phonons and flat phonon bands in moiré materials
• Raman imaging of twist angle variations in twisted bilayer graphene at intermediate angles
• Identification and Structural Characterization of Twisted Atomically Thin Bilayer Materials by Deep Learning
• Doping fingerprints of spin and lattice fluctuations in moiré superlattice systems
• Equilibrium Parametric Amplification in Raman-Cavity Hybrids
• Mesoscopic Stacking Reconfigurations in Stacked van der Waals Film