Title
Ballistic supercurrent discretization and micrometer-long Josephson coupling in germanium
Author
Hendrickx, N.W.
Tagliaferri, M.L.V.
Kouwenhoven, M.
Li, R.
Franke, D.P.
Sammak, A.
Brinkman, A.
Scappucci, G.
Veldhorst, M.
Publication year
2019
Abstract
We fabricate Josephson field-effect transistors in germanium quantum wells contacted by superconducting aluminum and demonstrate supercurrents carried by holes that extend over junction lengths of several micrometers. In superconducting quantum point contacts we observe discretization of supercurrent, as well as Fabry-Perot resonances, demonstrating ballistic transport. The magnetic field dependence of the supercurrent follows a clear Fraunhofer-like pattern, and Shapiro steps appear upon microwave irradiation. Multiple Andreev reflections give rise to conductance enhancement and evidence a transparent interface, confirmed by analyzing the excess current. These demonstrations of ballistic superconducting transport are promising for hybrid quantum technology in germanium. A© 2019 American Physical Society.
Subject
Ballistics
Germanium
Micrometers
Microwave irradiation
Point contacts
Quantum chemistry
Ballistic transports
Germanium quantum wells
Josephson coupling
Josephson field effect transistors
Magnetic field dependences
Multiple andreev reflections
Quantum point contact
Quantum technologies
Field effect transistors
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http://resolver.tudelft.nl/uuid:bd3c26ab-064a-4452-a355-a8f81a6a05a6
TNO identifier
865629
Publisher
American Physical Society
ISSN
2469-9950
Source
Physical Review B, 99 (7)
Article number
075435
Document type
article