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HL: Fachverband Halbleiterphysik

HL 28: Transport properties

HL 28.7: Vortrag

Dienstag, 26. Februar 2008, 11:00–11:15, ER 164

electronic transport in graphene nanoribbons calculated with recursive green's functions — •hengyi xu¹, igor zozoulenko², and thomas heinzel¹ — ¹Heinrich-Heine Universität, Düsseldorf, Germany — ²Department of Science and Technology, Linköping University, Sweden

Graphene demonstrates some unique electronic properties. We have developed the recursive Green's function technique within the tight-binding model for the mesoscopic graphene which provides a simple and elegant way of accounting for the effects of the contacts. The nanoribbon and the contacts are assumed to be made of graphene and are modeled by appropriate on-site and hopping parameters. Based on this technique, we study the electronic states and transport properties of the narrow graphene ribbons with zigzag and armchair edges. The energy spectra with zigzag and armchair edges are similar to those of the armchair and zigzag carbon nanotubes. Using the Landauer formula approach, the mode-dependent conductance through the electrostatic potential barriers in the graphene ribbons is investigated. We found that the quantized conductance as a function of Fermi energy exhibits the coherent oscillations in the zigzag edge graphene. Also, conductance dips are present which are absent in the armchair edge graphene. In addition, electronic transport in the presence of disorder is studied.