Abstract
We report on properties of Nb(/Ti)–carbon–(Ti/)Nb junctions fabricated on graphite flakes using e-beam lithography. The devices were characterized at temperatures above 1.8 K where a Josephson current was not observed, but the differential conductivity revealed features below the critical temperature of Nb, and overall metallic conductivity, in spite of a high-junctions resistance. Since the conductivity of graphite along the planes is essentially two-dimensional (2D), we use a theoretical model developed for metal/graphene junctions for interpretation of the results. The model involves two very different graphene “access” lengths. The shorter length characterizes ordinary tunneling between the three-dimensional Nb(/Ti) electrode and 2D graphene, while the second, much longer length, is associated with the Andreev reflections (AR) inside the junction and involves also “reflectionless” AR processes. The relevant transmission factors are small in the first case and much larger in the second, which explains ...
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
