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Regensburg 2016 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 30: Transport: Graphene
(Joint session of DS, DY, HL, MA, O and TT, organized by TT)

DS 30.3: Vortrag

Mittwoch, 9. März 2016, 10:15–10:30, H22

Dirac fermion wave packets in oscillating potential barriersWalter Pötz1, Sergey E. Savel’ev2, Peter Hänggi3, and •Wolfgang Häusler31Karl Franzens Univ. Graz, Inst. Phys., A-8010 Graz, Austria — 2Department of Physics, Loughborough University, Loughborough LE11 3TU, United Kingdom — 3Institut für Physik, Univ. Augsburg, 86135 Augsburg, Germany

We integrate the time-dependent (2+1)D Dirac equation for massless fermions in graphene or topological insulator surfaces. A recently developed staggered-grid leap-frog scheme is employed [1,2]. We consider an initial Gaussian wave packet which moves in the x-direction towards a potential barrier that is homogeneous along y and oscillates periodically in time. As for the x-dependence, we investigate square-well, sinusoidal, and linear-ramp potential profiles. Small transversal momentum components ky of the wave packet were analyzed analytically [3] and predicted to generate non-zero current densities jy, even at normal incidence ky=0 [4]. These findings are consistent with the present numerical studies of particle-, current-, and spin-density. We also investigate massive fermions: regarding some properties they resemble massless fermions, regarding other properties, however, peculiar intrinsic oscillations, reminiscent of Zitterbewegung, appear.
R. Hammer and W. Pötz, PRB 88, 235119 (2013)
R. Hammer et al., J. Comp. Phys. 265, 50 – 70 (2014)
S.E. Savel’ev, W. Häusler, and P. Hänggi, PRL 109, 226602 (2012)
S.E. Savel’ev, W. Häusler, and P. Hänggi, EPJB 86, 433 (2013).

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