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  • Phase tuning of multiple Andreev reflections of Dirac fermions and the Josephson supercurrent in Al–MoTe 2 –Al junctions
Title: Phase tuning of multiple Andreev reflections of Dirac fermions and the Josephson supercurrent in Al–MoTe 2 –Al junctions
When an electron is incident on a superconductor from a metal, it is reflected as a hole in a process called Andreev reflection. If the metal N is sandwiched between two superconductors S in an SNS junction, multiple Andreev reflections (MARs) occur. We have found that, in SNS junctions with high transparency ( τ   →   1 ) based on the Dirac semimetal MoTe 2 , the MAR features are observed with exceptional resolution. By tuning the phase difference φ between the bracketing Al superconductors, we establish that the MARs coexist with a Josephson supercurrent I s = I A   sin φ . As we vary the junction voltage V , the supercurrent amplitude I A varies in step with the MAR order n , revealing a direct relation between them. Two successive Andreev reflections serve to shuttle a Cooper pair across the junction. If the pair is shuttled coherently, it contributes to I s . The experiment measures the fraction of pairs shuttled coherently vs. V . Surprisingly, superconductivity in MoTe 2 does not affect the MAR features.  more » « less
Award ID(s):
2011750
PAR ID:
10413549
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Proceedings of the National Academy of Sciences
Volume:
119
Issue:
28
ISSN:
0027-8424
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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