Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 103: Transport: Poster Session

TT 103.8: Poster

Donnerstag, 19. März 2015, 15:00–18:00, Poster B

Scattering of two-dimensional Dirac fermions on gate-defined oscillating quantum dots — •Christian Schulz, Rafael L. Heinisch, and Holger Fehske — Universität Greifswald, Greifswald, Deutschland

Within an effective Dirac-Weyl theory we solve the scattering problem for massless chiral fermions impinging on a cylindrical time-dependent potential barrier. The set-up we consider can be used to model the electron propagation in a monolayer of graphene with harmonically driven quantum dots. For static small-sized quantum dots scattering resonances enable particle confinement and interference effects may switch forward scattering on and off. In addition to these phenomena, an oscillating quantum dot may cause the excitation of partial waves belonging to high energy states. This essentially modifies the resonance structures. For example, the scattering efficiency of an around the Dirac energy symmetric oscillating dot remains finite in the limit of low particle energies and small potential amplitudes. For an asymmetric oscillating dot, the partial wave resonances at higher energies are smeared out for small frequencies or large oscillation amplitudes, thereby dissolving the dot-bound states.