Merged Four Dirac Points at the Critical Interlayer Distance in Commensurately Twisted Bilayer Graphene: the Origin of the Zero Velocity
arXiv:2001.01364 · doi:10.7566/JPSJ.90.024703
Abstract
We study the commensurately-tilted bilayer graphene in the tight-binding model with changing the interlayer distance, which can be tuned by pressure. We find that at the commensurately-tilted bilayer graphene with moderate rotating angles, when the energy gap at K point is not negligible, the other Dirac points within the upper two bands move along the -K-M line in the bilayer Brillouzone, when the interlayer distance is changed. The velocity at K point becomes zero due to the merging of the four Dirac points within upper two bands. This mechanism of zero velocity at K point is expected to be the origin of the magic angle with flat band at ambient pressure, at which the upper two bands are almost degenerate and the band gap at K can be neglected.
arXiv comment10 pages 13 figures
References in corpus (26)
- The electronic properties of graphene
- Magic-angle graphene superlattices: a new platform for unconventional superconductivity
- Correlated Insulator Behaviour at Half-Filling in Magic Angle Graphene Superlattices
- Moire bands in twisted double-layer graphene
- Tuning superconductivity in twisted bilayer graphene
- Graphene bilayer with a twist: electronic structure
- Flat Bands in Slightly Twisted Bilayer Graphene
- Origin of Magic Angles in Twisted Bilayer Graphene
- Lattice relaxation and energy band modulation in twisted bilayer graphenes
- Origin of Mott insulating behavior and superconductivity in twisted bilayer graphene
- Commensuration and Interlayer Coherence in Twisted Bilayer Graphene
- Electronic structure of turbostratic graphene
- Electronic properties of graphene-based bilayer systems
- Energy Spectrum and Quantum Hall Effect in Twisted Bilayer Graphene
- Pressure dependence of the magic twist angle in graphene superlattices
- Engineering artificial graphene in a two-dimensional electron gas
- Electronic spectrum of twisted bilayer graphene
- Multiple topological transitions in twisted bilayer graphene near the first magic angle
- Commensurate-incommensurate phase transition in bilayer graphene
- Electrically Tunable Flat Bands and Magnetism in Twisted Bilayer Graphene
- Quantum Hall effect and the topological number in graphene
- Single-electron gap in the spectrum of twisted bilayer graphene
- Periodic Landau gauge and Quantum Hall effect in twisted bilayer graphene
- Localization of massless Dirac particles via spatial modulations of the Fermi velocity
- Merging Dirac points and topological phase transitions in the tight-binding model on the generalized honeycomb lattice
- Zero modes, energy gap, and edge states of anisotropic honeycomb lattice in a magnetic field