Structure and electronic states of a graphene double vacancy with an embedded Si dopant
- Author(s)
- Reed Nieman, Adelia J. A. Aquino, T.P. Hardcastle, Jani Kotakoski, Toma Susi, Hans Lischka
- Abstract
Silicon represents a common intrinsic impurity in graphene, bonding to either three or four carbon neighbors, respectively, in a single or double carbon vacancy. We investigate the effect of the latter defect (Si-C
4) on the structural and electronic properties of graphene using density functional theory. Calculations based both on molecular models and with periodic boundary conditions have been performed. The two-carbon vacancy was constructed from pyrene (pyrene-2C) which was then expanded to circumpyrene-2C. The structural characterization of these cases revealed that the ground state is slightly non-planar, with the bonding carbons displaced from the plane by up to ±0.2 Å. This non-planar structure was confirmed by embedding the defect into a 10 × 8 supercell of graphene, resulting in 0.22 eV lower energy than the previously considered planar structure. Natural bond orbital analysis showed sp
3 hybridization at the silicon atom for the non-planar structure and sp
2d hybridization for the planar structure. Atomically resolved electron energy loss spectroscopy and corresponding spectrum simulations provide a mixed picture: a flat structure provides a slightly better overall spectrum match, but a small observed pre-peak is only present in the corrugated simulation. Considering the small energy barrier between the two equivalent corrugated conformations, both structures could plausibly exist as a superposition over the experimental time scale of seconds.
- Organisation(s)
- Physics of Nanostructured Materials
- External organisation(s)
- Texas Tech University, Tianjin University, SuperSTEM Laboratory, University of Leeds
- Journal
- Journal of Chemical Physics
- Volume
- 147
- No. of pages
- 9
- ISSN
- 0021-9606
- Publication date
- 11-2017
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 104017 Physical chemistry, 103009 Solid state physics
- Keywords
- ASJC Scopus subject areas
- Physics and Astronomy(all), Physical and Theoretical Chemistry
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/structure-and-electronic-states-of-a-graphene-double-vacancy-with-an-embedded-si-dopant(39686d1f-9e48-4e9b-b049-9ce389547866).html