Hofstadter butterfly and the quantum Hall effect in twisted double bilayer graphene
J. A. Crosse, Naoto Nakatsuji, Mikito Koshino, Pilkyung Moon
Abstract
The two distinct configurations of twisted double bilayer graphene have different valley Chern numbers in spite of the similarity between their band structures. Here, the authors show that such a topological difference results in significantly different energy spectra and valley Hall conductivities in a uniform magnetic field. In addition, the authors show that the lattice symmetry protects the valley degeneracy of the Landau levels in one of the systems, while such degeneracy is absent in the other.
Topics & Concepts
Bilayer grapheneLandau quantizationQuantum Hall effectCondensed matter physicsPhysicsGrapheneDegeneracy (biology)Magnetic fieldLattice (music)Symmetry (geometry)Quantum mechanicsGeometryMathematicsBiologyAcousticsBioinformaticsGraphene research and applicationsTopological Materials and PhenomenaQuantum and electron transport phenomena