Coupling and Decoupling of Bilayer Graphene Monitored by Electron Energy Loss Spectroscopy
Yung‐Chang Lin, Amane Motoyama, Pablo Solís‐Fernández, Rika Matsumoto, Hiroki Ago, Kazu Suenaga
Abstract
We studied the interlayer coupling and decoupling of bilayer graphene (BLG) using spatially resolved electron energy loss spectroscopy with a monochromated electron source. We correlated the twist-angle-dependent energy band hybridization with Moiré 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 gap and results in the elimination of the vHS peak.
Topics & Concepts
Bilayer grapheneSpectroscopyGrapheneElectronMolecular physicsDecoupling (probability)van der Waals forceMonolayerElectron energy loss spectroscopyBilayerAbsorption spectroscopyVan Hove singularityCondensed matter physicsMaterials scienceChemistryPhysicsOpticsNanotechnologyMoleculeFermi levelEngineeringOrganic chemistryMembraneBiochemistryControl engineeringQuantum mechanicsGraphene research and applicationsMolecular Junctions and NanostructuresQuantum and electron transport phenomena