Berlin 2018 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 82: Topological Insulators II (joint session TT/MA)

TT 82.10: Talk

Thursday, March 15, 2018, 12:00–12:15, A 053

Helical Andreev bound states and non-sinusoidal current-phase relationship at the surface of topological insulators — •Niklas Krainovic, Grigory Tkachov, and Ewelina Maria Hankiewicz — Institute for Theoretical Physics and Astrophysics, University of Würzburg, D-97074 Würzburg, Germany

When a conventional superconductor is brought in close proximity to a three-dimensional topological insulator (3D TI), an unconventional triplet pairing is generated at the TI surface. Josephson junctions based on such hybrids support Andreev bound states (ABSs) that inherit the helical spin polarization of the normal TI, resulting in the non-sinusoidal Josephson current-phase relationship (CPR) [1,2]. Here, we present detailed analytic calculations of the non-sinusoidal CPR in the metallic regime and close to the Dirac point. The CPR exhibits strong forward skewness caused by a reflectionless transport channel perpendicular to the junction interface.

This work has been supported by the DFG Grant No TK60/4-1, by SFB 1170 8220 ToCoTronics 8221 and the ENB Graduate School on Topological Insulators.
G. Tkachov, E. M. Hankiewicz, Phys. Rev. B 88, 075401 (2013).
I. Sochnikov, L. Maier, C. A. Watson, J. R. Kirtley, C. Gould, G. Tkachov, E. M. Hankiewicz, C. Bruene, H. Buhmann, L. W. Molenkamp, and K. A. Moler, Phys. Rev. Lett. 114, 066801 (2015).