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O: Fachverband Oberflächenphysik

O 57: Graphene: SiC Substrates and Intercalation (jointly with HL, MA and TT)

O 57.4: Vortrag

Mittwoch, 13. März 2013, 16:45–17:00, H17

Electronic structure of epitaxial graphene on 3C-SiC(111) — •Lydia Nemec, Volker Blum, Patrick Rinke, and Matthias Scheffler — Fritz-Haber-Institut der Max-Planck-Gesellschaft, D-14195 Berlin

We present a study of the electronic structure of the carbon-rich surface phases on 3C-SiC(111), including quasi-freestanding graphene and intercalated phases. Our approach is based on density-functional theory (DFT) including van der Waals (vdW) dispersion terms in the Tkatchenko-Scheffler approach [1]. We use semilocal DFT (PBE+vdW functional) for our first-principles structure predictions. For the oxygen intercalated bilayer graphene, we consider an oxygen-rich interface passivating the Si dangling bonds [2]. Based on the predicted geometries, hybrid functionals (HSE06 and PBE0) are used to assess the electronic structure of: (1) the partially sigma-bonded "buffer layer" phase, (2) quasi-freestanding graphene up to three monolayers, and (3) hydrogen- and oxygen intercalated graphene phases. For the different phases, we discuss the changes of the electronic structure, addressing the influence of the intercalated material on the doping of the graphene and the charge transfer from the substrate to the graphene layer. We observe that in the intercalated phases graphene is decoupled from the substrate, making intercalation a promising approach for further studies.

[1] A. Tkatchenko, M. Scheffler, PRL 102, 073005 (2009).

[2] M.H. Oliveira et al.; Carbon 52, 83-89 (2013).