Flat bands near Fermi level of topological line defects on graphite

Here, we report direct experimental evidence for the presence of flat bands, close to the Fermi level, in one-dimensional topological defects of graphite. The flat bands are manifested by a pronounced peak in the tunnelling density of states. Our ab initio calculations indicate that the flat bands with vanishing Fermi velocity originate from sp(2) dangling bonds (with antibonding nature) of undercoordinated carbon atoms at the edges of the defects. We further demonstrate that the presence of flat bands could be an inevitable behavior of ID defects of graphene/graphite with undercoordinated carbon atoms at the edges of the defects. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4752441]