Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 33: Transport: Majorana Fermions

TT 33.4: Vortrag

Dienstag, 21. März 2017, 14:45–15:00, HSZ 204

Josephson effect in topologically confined channels — •Daniel Frombach and Patrik Recher — Institut für Mathematische Physik, TU Braunschweig

In recent times the fractional Josephson effect has been used as a signature of Majorana fermions forming in Josephson junctions mediated by the topologically protected spin helical edge states of a quantum spin Hall insulator [1].

Here we propose a setup based on silicene in which either a single spin helical Kramers pair of edge states [2] or two sets of Kramers pair edge stets can exist at domain walls depending on an externally applied inhomogeneous electrical field. We furthermore investigate a Josephson junction mediated by these edge states through the Bogoliubov de Gennes formalism. We show that the energy phase relation is 4 π periodic when the system is in the quantum spin Hall regime but changes to a 2 π periodicity due to backscattering effects when two sets of Kramers pair edge states are present.

[1] L. Fu and C.L. Kane, Phys. Rev. B 79, 161408 (2009).

[2] M. Ezawa, New Journal of Physics 14, 033003 (2012).