Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 26: Transport: Graphene and Carbon Nanotubes
TT 26.4: Vortrag
Mittwoch, 25. März 2009, 15:00–15:15, HSZ 03
Exchange phenomena in transport across graphene armchair nanoribbon quantum dots — •Sonja Koller1, Leonhard Mayrhofer1,2, and Milena Grifoni1 — 1Universität Regensburg — 2Fraunhofer IWM Freiburg
Taking into account interaction effects, we have investigated spectrum and transport properties of finite size graphene armchair nanoribbons (ACNRs). In wide ribbons, the long-ranged part of the Coulomb interaction dominates, yielding charging and spin-charge separation effects. For narrow ribbons, short-ranged processes become relevant. Those can involve not only two bulk electrons, but also one bulk electron and one electron localized in an edge state, which arises at both zig-zag ends of the stripe. In particular, this edge-bulk interaction strongly influences spectrum and transport properties of the system. In transport, the most prominent feature is the occurrence of a pronounced negative differential conductance for a completely symmetric, unpolarized setup. Further, we discuss the transport characteristics of ACNRs in magnetic field and with collinearly polarized contacts.