Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 44: Graphene: Electronic Properties, Structure and Substrate Interaction
O 44.1: Poster
Dienstag, 8. März 2016, 18:15–20:30, Poster E
Effect of electron-density inhomogeneities on the electronic band structure of single-layer graphene — •Trevor Clarke1,2, Peter Kot1,2, Jon Parnell1,2, Sina Habibian1,2, Klaus Kern1,3, and Christian R. Ast1 — 1Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany — 2University of British Columbia, Vancouver, Canada — 3École Polytechnique Fédérale de Lausanne, Switzerland
In an ideal graphene sheet, the density of electrons is uniformly distributed throughout the two-dimensional lattice. However, in experimental contexts, graphene sheets are routinely subject to electron-density inhomogeneities. Such inhomogeneities, or charge puddles, are thought to arise from charged impurities located on the substrate on which the graphene is deposited. To investigate the effects of charge puddles on the electronic properties of single-layer graphene, we simulate fluctuating potential landscapes that model charge inhomogeneities via two methods: the diamond-square algorithm, and fractional Brownian motion (with Perlin noise). Each method produces randomly fluctuating (but smooth and continuous) potential landscapes with unique features and characteristics. These potential landscapes are used to perturb the on-site energies of the carbon atoms in the lattice. The band structure of the perturbed lattice is then calculated using a tight-binding model. We present calculations exploring a range of parameter values, and indicate results produced from values which generate potentials that most closely resemble empirical findings.