2010/10/19 by Adina Luican, A. Luican, Guohong Li +12 · 2 citations
Materials Science · Physics and Astronomy · #Graphene research and applications #Quantum and electron transport phenomena #Topological Materials and Phenomena #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevlett.106.126802
published as Phys. Rev. Lett. 106, 126802 (2011) · 10 pages, 4 figures
arxiv created 2010/10/19 · openalex publication_date 2011/03/21 · arxiv updated 2011/04/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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° the low energy carriers exhibit Landau level spectra characteristic of massless Dirac fermions. Above 20° the layers effectively decouple and the electronic properties are indistinguishable from those in single-layer graphene, while for smaller angles we observe a slowdown 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.