Coupling and decoupling of bilayer graphene monitored by electron energy loss spectroscopy

Abstract

We studied the interlayer coupling and decoupling of bilayer graphene (BLG) by using spatially resolved electron energy loss spectroscopy (EELS) with a monochromated electron source. We correlated the twist-angle-dependent energy band hybridization with Moire superlattices and the corresponding optical absorption peaks. The optical absorption peak originates from the excitonic transition between the hybridized van Hove singularities (vHSs), which shifts systematically with the twist angle. We then proved that the BLG decouples when a monolayer of metal chloride is intercalated in its van der Waals (vdW) gap, and results in the elimination of the vHS peak.

References in corpus (7)

• 2D materials and van der Waals heterostructures
• Mixed-Dimensional van der Waals Heterostructures
• Resonantly hybridised excitons in moiré superlattices in van der Waals heterostructures
• Continuum Model of the Twisted Bilayer
• Numerical studies of confined states in rotated bilayers of graphene
• Exciton mapping at subwavelength scales in two-dimensional materials
• Electron spectroscopy of single quantum objects to directly correlate the local structure to their electronic transport and optical properties

Cited by in corpus (4)

• Determining the Twist Angle of Bilayer Graphene by Machine Learning Analysis of its Raman Spectrum
• Tunable Interband Transitions in Twisted h-BN/Graphene Heterostructures
• Reduction of Interlayer Interaction in Multilayer Stacking Graphene with Carbon Nanotube Insertion: Insights from Experiment and Simulation
• Direct observation of locally modified excitonic effect within a moiré unit cell in twisted bilayer graphene