title: Critical Current Scaling in Long Diffusive Graphene-Based Josephson Junctions.
abstract: We present transport measurements on long, diffusive, graphene-based Josephson junctions. Several junctions are made on a single-domain crystal of CVD graphene and feature the same contact width of ∼9 μm but vary in length from 400 to 1000 nm. As the carrier density is tuned with the gate voltage, the critical current in these junctions ranges from a few nanoamperes up to more than 5 μA, while the Thouless energy, ETh, covers almost 2 orders of magnitude. Over much of this range, the product of the critical current and the normal resistance ICRN is found to scale linearly with ETh, as expected from theory. However, the value of the ratio ICRN/ETh is found to be 0.1-0.2, which much smaller than the predicted ∼10 for long diffusive SNS junctions.
authors.affiliation: Department of Physics, Duke University , Durham, North Carolina 27708, United States.
authors.forename: Chung Ting
authors.initials: CT
authors.lastname: Ke
authors.affiliation: Department of Applied Physics, The University of Tokyo , Tokyo 113-8654, Japan.
authors.forename: Ivan V
authors.initials: IV
authors.lastname: Borzenets
authors.affiliation: Department of Physics, Duke University , Durham, North Carolina 27708, United States.
authors.forename: Anne W
authors.initials: AW
authors.lastname: Draelos
authors.affiliation: Department of Physics, Duke University , Durham, North Carolina 27708, United States.|Department of Physics, Appalachian State University , Boone, North Carolina 28608, United States.
authors.forename: Francois
authors.initials: F
authors.lastname: Amet
authors.affiliation: Department of Physics, Duke University , Durham, North Carolina 27708, United States.
authors.forename: Yuriy
authors.initials: Y
authors.lastname: Bomze
authors.affiliation: College of Engineering, Mathematics and Physical Sciences, University of Exeter , Exeter, Devon EX4, United Kingdom.
authors.forename: Gareth
authors.initials: G
authors.lastname: Jones
authors.affiliation: College of Engineering, Mathematics and Physical Sciences, University of Exeter , Exeter, Devon EX4, United Kingdom.
authors.forename: Monica
authors.initials: M
authors.lastname: Craciun
authors.affiliation: College of Engineering, Mathematics and Physical Sciences, University of Exeter , Exeter, Devon EX4, United Kingdom.
authors.forename: Saverio
authors.initials: S
authors.lastname: Russo
authors.affiliation: Department of Applied Physics, The University of Tokyo , Tokyo 113-8654, Japan.
authors.forename: Michihisa
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Applied Physics, The University of Tokyo , Tokyo 113-8654, Japan.|RIKEN, Center for Emergent Matter Science , Tokyo 351-0198, Japan.
authors.forename: Seigo
authors.initials: S
authors.lastname: Tarucha
authors.affiliation: Department of Physics, Duke University , Durham, North Carolina 27708, United States.
authors.forename: Gleb
authors.initials: G
authors.lastname: Finkelstein
keywords: Graphene; Josephson junction; Thouless energy; diffusive SNS junction; superconductivity