Flat Bands in Slightly Twisted Bilayer Graphene

Abstract

The bands of graphite are extremely sensitive to topological defects which modify the electronic structure. In this paper we found non-dispersive flat bands no farther than 10 meV of the Fermi energy in slightly twisted bilayer graphene as a signature of a transition from a parabolic dispersion of bilayer graphene to the characteristic linear dispersion of graphene. This transition occurs for relative rotation angles of layers around $1.5^o$ and is related to a process of layer decoupling. We have performed ab-initio calculations to develop a tight binding model with an interaction Hamiltonian between layers that includes the $\pi$ orbitals of all atoms and takes into account interactions up to third nearest-neighbors within a layer.

6 pages, 4 figures

References in corpus (4)

• Electric Field Effect in Atomically Thin Carbon Films
• Kohn-Luttinger superconductivity in graphene
• Character of electronic states in graphene antidot lattices: Flat bands and spatial localization
• Low energy excitations in graphite: The role of dimensionality and lattice defects