Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 42: Superconductivity: Tunneling and Josephson Junctions
TT 42.3: Vortrag
Donnerstag, 20. März 2025, 10:00–10:15, H32
Current Phase Relation of HgTe Nanowire Josephson Junctions in an Axial Magnetic Field — •Niklas Hüttner1, Wolfgang Himmler1, Ralf Fischer1, Dmitriy Kozlov1, Michael Barth2, Jacob Fuchs2, Andreas Costa2, Klaus Richter2, Leandro Tosi1, Nicola Paradiso1, Dieter Weiss1, and Christoph Strunk1 — 1Institute for Experimental and Applied Physics, University of Regensburg — 2Institute for Theoretical Physics, University of Regensburg, 93053 Regensburg, Germany
Proximitized semiconductor nanowires are expected to show Anomalous Josephson effect by spin-orbit interaction and Zeeman effect in a magnetic field parallel to the wire direction [1]. The ϕ0 shift is accompanied by a direction dependent critical current (Superconducting diode effect).1 We directly probe the current phase relation (CPR) of HgTe nanowires proximitized by niobium leads via an asymmetric SQUID measurement. The topological surface states additionally pick up an Aharanov Bohm phase for B∥ in wire direction [2]. We observe an highly tunable ϕ0 shift, a 0-π transition, and a superconducting diode effect from the corresponding CPRs. Additionally a strong modulation of both the critical current and the content of higher harmonics is observed for magnetic flux between 0 and 1.5Φ0.
[1] T. Yokoyama et al., Phys. Rev. B 89, 195407 (2014).
[2] W. Himmler et al., Phys. Rev. Res. 5, 043021 (2023).
Keywords: 3D-Topological Insulator; Ballistic Josephson junctions; HgTe; Anomalous current phase relation