Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 55: Graphene
O 55.2: Poster
Dienstag, 21. März 2017, 18:30–20:30, P2-EG
The effect of defects on the band structure of graphene near the Dirac point — •Piotr Kot1,2, Jonathan Parnell2, Sina Habibian2, and Christian R. Ast1 — 1Max Planck Institute for Solid State Research, Stuttgart, Germany — 2University of British Columbia, Vancouver, Canada
Using a simple real-space tight-binding model, we present the effect of defects on the band structure of graphene in momentum space near the Dirac point. While several of the calculated defects strongly alter the band dispersion and line width near the Dirac point, we find that a band gap forms only in systems where atoms are missing from one sublattice. Another finding of note is that some specific defects open a band gap with broadened, but not entirely delocalized, states in the gap. These band gaps with broadened states strongly resemble ”elongated” Dirac points that have been experimentally found by photoemission spectroscopy and have been discussed in the literature. We surmise that these ”elongated” Dirac points are, at least in part, due to specific defects in the graphene. Our findings also point to obstacles to opening a band gap in graphene, which have to be considered.