2013/12/25 by Angela Kou, Benjamin E. Feldman, A. J. Levin +5 · 130 citations
Chemistry · Materials Science · Mathematics · Physics and Astronomy · #Bilayer #Bilayer graphene #Chemistry #Condensed matter physics #Coulomb #Degeneracy (biology) #Electron #Fractional quantum Hall effect #Graphene #Graphene research and applications #Landau quantization #Mathematics #Physics #Quantum Hall effect #Quantum and electron transport phenomena #Quantum mechanics #Quantum spin Hall effect #Spin (aerodynamics) #Symmetry (geometry) #Topological Materials and Phenomena #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1126/science.1250270
published in Science 345(6192), 55-57 (American Association for the Advancement of Science)
arxiv created 2013/12/25 · openalex publication_date 2014/05/30 · arxiv updated 2014/07/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The nature of fractional quantum Hall (FQH) states is determined by the interplay between the Coulomb interaction and the symmetries of the system. The distinct combination of spin, valley, and orbital degeneracies in bilayer graphene is predicted to produce an unusual and tunable sequence of FQH states. Here, we present local electronic compressibility measurements of the FQH effect in the lowest Landau level of bilayer graphene. We observe incompressible FQH states at filling factors ν = 2p + 2/3, with hints of additional states appearing at ν = 2p + 3/5, where p = -2, -1, 0, and 1. This sequence breaks particle-hole symmetry and obeys a ν → ν + 2 symmetry, which highlights the importance of the orbital degeneracy for many-body states in bilayer graphene.