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 1.5o 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 π orbitals of all atoms and takes into account interactions up to third nearest-neighbors within a layer.
@article{arxiv.1012.4320,
title = {Flat Bands in Slightly Twisted Bilayer Graphene},
author = {E. Suárez Morell and J. D. Correa and P. Vargas and M. Pacheco and Z. Barticevic},
journal= {arXiv preprint arXiv:1012.4320},
year = {2010}
}