Conditions for Conductance Quantization in Mesoscopic Dirac Systems on the Examples of Graphene Nanoconstrictions |

G. Rut and A. Rycerz
Marian Smoluchowski Institute of Physics, Jagiellonian University, W.S. Reymonta 4, PL-30-059 Kraków, Poland |

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Ballistic transport through an impurity-free section of the Corbino disk in graphene is investigated by means of the Landauer-Büttiker formalism in the mesoscopic limit. In the linear-response regime the conductance is quantized in steps close to integer multiples of 4e^{2}/h, yet Fabry-Perot oscillations are strongly suppressed. The quantization arises for small opening angles θ ≲ π/3 and large radii ratios R_{2}/R_{1}≳ 10. We find that the condition for emergence of the n-th conductance step can be written as √nθ/π ≪ 1. A brief comparison with the conductance spectra of graphene nanoribbons with parallel edges is also provided. |

DOI: 10.12693/APhysPolA.126.A-114 PACS numbers: 73.63.-b, 72.80.Vp, 81.07.Vb |