Resonant scattering in graphene with a gate-defined chaotic quantum dot

Abstract

We investigate the conductance of an undoped graphene sheet with two metallic contacts and an electrostatically gated island (quantum dot) between the contacts. Our analysis is based on the Matrix Green Function formalism, which was recently adapted to graphene by Titov {\em et al.} [Phys.\ Rev.\ Lett.\ {\bf 104}, 076802 (2010)]. We find pronounced differences between the case of a stadium-shaped dot (which has chaotic classical dynamics) and a disc-shaped dot (which has integrable classical dynamics) in the limit that the dot size is small in comparison to the distance between the contacts. In particular, for the stadium-shaped dot the two-terminal conductance shows Fano resonances as a function of the gate voltage, which cross-over to Breit-Wigner resonances only in the limit of completely separated resonances, whereas for a disc-shaped dot sharp Breit-Wigner resonances resulting from higher angular momentum remain present throughout.

12 pages, 4 figures

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Cited by in corpus (10)

• Chaos in Dirac electron optics: Emergence of a relativistic quantum chimera
• Optimal traps in graphene
• Interplay of Aharonov-Bohm and Berry phases in gate-defined graphene quantum dots
• Density of states as a probe of electrostatic confinement in graphene
• Gate-tunable regular and chaotic electron dynamics in ballistic bilayer graphene cavities
• Resonant finite-size impurities in graphene, unitary limit and Friedel oscillations
• Decay of semiclassical massless Dirac fermions from integrable and chaotic cavities
• Electronic scattering, focusing, and resonance by a spherical barrier in Weyl semimetals
• Electronic transport in graphene with particle-hole-asymmetric disorder
• Zero-energy states in graphene quantum dot with wedge disclination