Dresden 2017 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 85: Topological Insulators III (joined session with TT)

HL 85.6: Vortrag

Freitag, 24. März 2017, 11:15–11:30, POT 251

Induced superconductivity in lateral topological Josephson junctions with (Sb_0.94Bi_0.06)₂Te₃ interlayer — •Daniel Rosenbach¹, Peter Schüffelgen¹, Martin Lanius¹, Gregor Mussler¹, Stefan Trellenkamp¹, Martin P. Stehno², Alexander Brinkman², Detlev Grützmacher¹, and Thomas Schäpers¹ — ¹Peter Grünberg Institute 9, Forschungszentrum Jülich, 52425 Jülich, Germany — ²MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands

The long sought Majorana fermion is predicted to arise in superconducting systems with p-wave pair correlation symmetry. Induced superconductivity in topological insulator thin films is expected to show partly p-wave pairing, such that Majorana zero modes (MZM) are thought to exist at the interface with a conventional s-wave superconductor. A current carried by these zero modes is supposed to show a doubled periodicity in the current-phase relation, compared to conventional modes.
Molecular beam grown topological insulator ternary alloy thin films, of given composition, with a thin aluminum-oxide capping layer, have been prepared with lateral niobium superconducting contacts. Junctions of various geometries have been measured at low temperatures. The response to an externally applied magnetic field and to a radio-frequency signal is strongly dependent on the current-phase relation of the conductive modes. Characterization therefore includes an analysis of various Fraunhofer diffraction pattern as well as Shapiro step measurements at different frequencies.