Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 49: Poster Session: Superconductivity
TT 49.29: Poster
Wednesday, April 3, 2019, 15:00–18:30, Poster D
Gate-tunable supercurrent in epitaxial Al-InAs-based Josephson junctions — •Christian Baumgartner1, Nicola Paradiso1, Geoffrey C. Gardner2, Michael J. Manfra2,3, and Christoph Strunk1 — 1Institute for Experimental and Applied Physics, University of Regensburg, 93040 Regensburg, Germany — 2Station Q Purdue, Purdue University, West Lafayette, Indiana 47907, USA — 3Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
Coupling an s-wave superconductor to a two-dimensional semiconductor with strong spin-orbit interaction (SOI) offers new technological and research opportunities. Carriers in proximitized semiconductors acquire superconducting correlations while maintaining the charge tunability and the long mean free path typical of high mobility semiconductors. In the presence of strong SOI and an external magnetic field, several exotic phenomena are expected to emerge as, e.g., anisotropic supercurrent and ϕ0-Josephson junctions.
We study SNS Josephson junctions where the SC is epitaxial Al and the weak link in between the banks is an InGaAs/InAs 2D electron gas. A challenge in the fabrication of such devices is the etching of the superconductor, which must preserve the high mobility of the 2DEG underneath. We demonstrate several working quantum point contacts and SNS junctions, whose supercurrent can be controlled by gating. A regular Fraunhofer pattern is observed, indicating a good homogeneity of the junction. These results constitute essential building block towards the implementation of more complex topological devices.