Regensburg 2010 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 37: MLT: Poster Session
TT 37.22: Poster
Donnerstag, 25. März 2010, 14:00–18:00, Poster A
Signatures of Klein tunneling in the Aharonov-Bohm effect in graphene rings — •Jörg Schelter1, Dan Bohr2, and Björn Trauzettel1 — 1Department of Theoretical Physics and Astrophysics, University of Würzburg, D-97074 Würzburg, Germany — 2Department of Physics and Astronomy, University of Basel, CH-4056 Basel, Switzerland
We numerically investigate the effect of Klein tunneling on the Aharonov-Bohm oscillations in graphene rings using a tight-binding model with nearest neighbor couplings. In order to introduce Klein tunneling into this system, we apply an electrostatic potential to one of the arms of the ring, such that this arm together with the two adjacent leads form either a nn′n- or npn-junction. The former case corresponds to normal tunneling and the latter case to Klein tunneling.
We find that the transmission properties strongly depend on the smoothness of the two pn-junctions in series. In particular, for sharp junctions the amplitude profile is symmetric around the charge neutrality point in the gated arm, whereas for smooth junctions the Aharonov-Bohm oscillations are strongly suppressed in the Klein tunneling regime.