Single Layer Behavior and Its Breakdown in Twisted Graphene Layers

Abstract

We report high magnetic field scanning tunneling microscopy and Landau level spectroscopy of twisted graphene layers grown by chemical vapor deposition. For twist angles exceeding ~3 degrees the low energy carriers exhibit Landau level spectra characteristic of massless Dirac fermions. Above 20 degrees the layers effectively decouple and the electronic properties are indistinguishable from those in single layer graphene, while for smaller angles we observe a slow-down of the carrier velocity which is strongly angle dependent. At the smallest angles the spectra are dominated by twist induced Van Hove singularities and the Dirac fermions eventually become localized. An unexpected electron-hole asymmetry is observed which is substantially larger than the asymmetry in either single or untwisted bilayer graphene.

10 pages, 4 figures

References in corpus (8)

• The electronic properties of graphene
• Epitaxial graphene
• Electronic states and Landau levels in graphene stacks
• Landau level spectroscopy of ultrathin graphite layers
• Scanning Tunneling Spectroscopy of Graphene on Graphite
• Cyclotron Resonance study of the electron and hole velocity in graphene monolayers
• Reduction of Fermi velocity in folded graphene observed by resonance Raman spectroscopy
• Electron-Phonon Interactions for Optical Phonon Modes in Few-Layer Graphene

Cited by in corpus (16)

• The electronic properties of bilayer graphene
• Continuum Model of the Twisted Bilayer
• Numerical studies of confined states in rotated bilayers of graphene
• Electronic properties of graphene: a perspective from scanning tunneling microscopy and magneto-transport
• Dynamical conductivity of AA-stacked bilayer graphene
• Topologically Protected Zero Modes in Twisted Bilayer Graphene
• Optical Conductivity of Twisted Bilayer Graphene
• Electronic Hybridization of Large-Area Stacked Graphene Films
• Electronic Properties of Twisted Trilayer Graphene
• The Coexistence of van Hove Singularities and Superlattice Dirac Points in a Slightly Twisted Graphene Bilayer
• Flat Bands near Fermi Level of Topological Line Defects on Graphite
• Enhanced Intervalley Scattering of Twisted Bilayer Graphene by Periodic AB Stacked Atoms
• Two Distinct Phases of Bilayer Graphene Films on Ru(0001)
• Ab-initio analysis of superstructures revealed by STM on bilayer graphene
• Twisted Bilayer Graphene Superlattices
• Twisted bi-layer graphene: microscopic rainbows