Dresden 2011 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 9: Graphene II (organised by TT)
DY 9.5: Vortrag
Montag, 14. März 2011, 15:00–15:15, HSZ 304
Transmission through electrostatic and magnetic barriers in the T3-lattice — •Daniel F. Urban1, Dario Bercioux1,2, and Wolfgang Häusler3 — 1Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany — 2Freiburg Institute for Advanced Studies, Albert-Ludwigs-Universität, D-79104 Freiburg, Germany — 3Institut für Physik, Universität Augsburg, D-86135 Augsburg, Germany
Albeit the T3-lattice exhibits a reciprocal lattice similar to graphene with two inequivalent Dirac-points at six corners of the hexagonal first Brillouin zone, where relativistic electron-hole symmetric bands touch, T3 differs and considerably generalizes graphene. A peculiarity of T3 is the occurance of an additional dispersionless energy band at energy E=0 and an enlarged pseudo-spin S=1 [1] instead of S=1/2 as for graphene. As a result, we find enhanced Klein tunneling through rectangular electrostatic barriers, compared to the case of graphene. Moreover, at the particular energy of half the barrier height we find even complete transparency, T=1, irrespective of barrier thickness and of incidence angle. We also investigate rectangular magnetic barriers and in this case identify regimes of zero barrier transparency, qualitatively similar to the case of graphene [2].
[1] D. Bercioux, D. F. Urban, H. Grabert, and W. Häusler, Phys. Rev. A 80, 063603 (2009).
[2] A. De Martino, L. Dell’Anna, and R. Egger, Phys. Rev. Lett. 98, 066802 (2007).