Proximity effect and interface transparency in Al/InAs-nanowire/Al diffusive junctions

We investigate the proximity effect in InAs nanowire (NW) junctions with superconducting contacts made of Al. The carrier density in InAs is tuned by means of the back gate voltage \(V_g\). At high positive \(V_g\) the devices feature transport signatures characteristic of diffusive junctions with h...

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Bibliographic Details
Published in:arXiv.org 2017-05
Main Authors: Bubis, A V, Denisov, A O, Piatrusha, S U, Batov, I E, Becker, J, Treu, J, Ruhstorfer, D, Koblmüller, G, Khrapai, V S
Format: Article
Language:English
Subjects:
Carrier density
Nanowires
Potential barriers
Proximity
Proximity effect (electricity)
Reduction
Online Access:Get full text
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Summary:We investigate the proximity effect in InAs nanowire (NW) junctions with superconducting contacts made of Al. The carrier density in InAs is tuned by means of the back gate voltage \(V_g\). At high positive \(V_g\) the devices feature transport signatures characteristic of diffusive junctions with highly transparent interfaces - sizable excess current, re-entrant resistance effect and proximity gap values (\(\Delta_N\)) close to the Al gap (\(\Delta_0\)). At decreasing \(V_g\), we observe a reduction of the proximity gap down to \(\Delta_N\approx\Delta_0/2\) at NW conductances \(\sim2e^2/h\), which is interpreted in terms of carrier density dependent reduction of the Al/InAs interface transparency. We demonstrate that the experimental behavior of \(\Delta_N\) is closely reproduced by a model with shallow potential barrier at the Al/InAs interface.
ISSN:2331-8422
DOI:10.48550/arxiv.1705.00443