Multiple Andreev reflections and Shapiro steps in a Ge-Si nanowire Josephson junction

Multiple Andreev reflections and Shapiro steps in a Ge-Si nanowire Josephson junction

Ridderbos, Joost (University of Twente)
Brauns, Matthias (University of Twente)
Li, Ang (Eindhoven University of Technology)
Bakkers, E.P.A.M. (TU Delft QN/Bakkers Lab; TU Delft QuTech Advanced Research Centre; Eindhoven University of Technology)
Brinkman, Alexander (University of Twente)
Van Der Wiel, Wilfred G. (University of Twente)
Zwanenburg, Floris A. (University of Twente)

2019

We present a Josephson junction based on a Ge-Si core-shell nanowire with transparent superconducting Al contacts, a building block which could be of considerable interest for investigating Majorana bound states, superconducting qubits, and Andreev (spin) qubits. We demonstrate the dc Josephson effect in the form of a finite supercurrent through the junction and establish the ac Josephson effect by showing up to 23 Shapiro steps. We observe multiple Andreev reflections up to the sixth order, indicating that charges can scatter elastically many times inside our junction and that our interfaces between superconductor and semiconductor are transparent and have low disorder.

http://resolver.tudelft.nl/uuid:3e3a1b43-3c95-4bef-8210-a1b630f3056e

https://doi.org/10.1103/PhysRevMaterials.3.084803

2475-9953

Physical Review Materials, 3 (8)

Institutional Repository

journal article

© 2019 Joost Ridderbos, Matthias Brauns, Ang Li, E.P.A.M. Bakkers, Alexander Brinkman, Wilfred G. Van Der Wiel, Floris A. Zwanenburg