Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 11: Topological insulators II (joint session HL/TT)

HL 11.9: Vortrag

Montag, 12. März 2018, 17:15–17:30, A 151

Low-dimensional topological Josephson junctions on selectively grown topological insulator nanoribbons — •Tobias W. Schmitt¹, Daniel Rosenbach¹, Peter Schüffelgen¹, Michael Schleenvoigt¹, Abdur R. Jalil¹, Chuan Li², Gregor Mussler¹, Stefan Trellenkamp¹, Alexander Brinkman², Detlev Grützmacher¹, and Thomas Schäpers¹ — ¹Peter Grünberg Institute 9, Forschungszentrum Jülich & JARA-FIT, 52425 Jülich, Germany — ²MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands

At the interface of a topological insulator and a s-wave superconductor, exotic Majorana modes are predicted to arise. In lateral topological Josephson junctions comprised of two superconducting leads on top of a topological insulator thin film, possible Majorana assisted transport is expected to occur in addition to conventional Andreev bound states. The latter superimpose the indications of Majorana excitations in Shapiro response measurements and make their detection more difficult. As the number of conventional Andreev bound states depends on the total number of conducting modes, their impact can be reduced in low-dimensional Josephson junctions. In our recent work, we focus on the realization of low-dimensional topological Josephson junctions by (I) selectively depositing TI nanoribbons of reduced width and (II) increasing of the Fermi wavelength by adjusting the Fermi level to the Dirac point of the linear disperse surface states. Such junctions have been prepared and characterized electrically at low temperatures, including their Fraunhofer diffraction pattern and their Shapiro response.