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TT: Fachverband Tiefe Temperaturen

TT 16: Poster: Transport

TT 16.9: Poster

Montag, 27. März 2023, 15:00–18:00, P2/OG4

Revealing the role of Klein tunneling in Aharanov-Bohm graphene rings — •Ching-Hung Chiu and Ming-Hao Liu — Department of Physics, National Cheng Kung University, Tainan City, Taiwan

Graphene, the ideal testbed of relativistic quantum mechanics, have been widely used to explore not only the exotic transport properties of Dirac fermions but also to confirm classic quantum-mechanical phenomena such as the Aharanov-Bohm effect. Motivated by a recent experiment [1], here we perform quantum transport simulations in the ballistic limit at zero temperature, considering an Aharanov-Bohm ring made of graphene with the same sample and gate geometry as the experiment. Preliminary properties from our simulations such as the gate and magnetic field dependence of the two-terminal conductance are rather consistent with the experiment, confirming their claim of the observed Aharanov-Bohm effect. To probe the effect of Klein tunneling, however, we propose a modified design using a local gate that makes pn interfaces perpendicular to the arm of the ring, different from the experiment. Based on our new design, we show that Klein tunneling may sharpen the Aharanov-Bohm oscillation frequency due to the screening of the transverse modes.

[1] J. Dauber et al., arXiv:2008.02556v3