Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 71: Poster Session: Graphene / Topological Insulators / Interfaces and Surfaces
HL 71.6: Poster
Mittwoch, 28. März 2012, 16:00–19:00, Poster D
Resonant scattering in graphene: adsorbate fingerprints from ab initio calculations — •Karri Saloriutta1, Martti J. Puska1, and Antti-Pekka Jauho2 — 1Department of Applied Physics, Aalto University School of Science, Finland — 2Department of Micro- and Nanotechnology, DTU Nanotech, Technical University of Denmark, Denmark
We have recently shown that by using a scaling approach for randomly distributed defects reliable estimates for transmission properties can be calculated based on even single defect calculations. This is done by defining a scattering cross-section, a quantity that only depends on energy and defect type. Estimates of transmission and all the related transport properties, such as localization lengths and mean free paths, can then be calculated for a macroscopic system with an arbitrary defect density.
We now extend our analysis to the case of adsorbates on graphene by studying the experimentally important epoxide and hydroxyl groups. We show that a qualitative understanding of resonant scattering can be gained even from a single bulk graphene calculation, which thus provides an useful transmission “fingerprint” for each adsorbate. For graphene nanoribbons on the other hand the scattering cross section needs to be calculated from an ensemble containing all the relevant adsorption sites across the whole ribbon. The transmission in ribbons is also strongly affected by the van Hove singularities at band edges making the scattering cross section specific to a particular ribbon width.