Critical current scaling in long diffusive graphene-based Josephson junctions
Draelos, Anne W.
Craciun, Monica F.
American Chemical Society
Reason for embargo
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.
C.-T. K. and G.F. were supported by the Division of Materials Sciences and Engineering, Office of Basic Energy Sciences, U.S. Department of Energy, under Award No. de-sc0002765. F.A. acknowledges support from the Fritz London postdoctoral fellowship and the ARO under Award W911NF-14-1-0349. I.V.B. and M.Y. are funded by the Canon foundation and Grants-in-Aid for Scientific Research on Innovative Areas, Science of Atomic Layers. S.T. acknowledges JSPS, Grant-in-Aid for Scientific Research S (26220710) and Project for Developing Innovation Systems of MEXT, Japan. S. R. and M. F. C. acknowledge financial support from EPSRC (Grant EP/J000396/1, EP/K017160, EP/K010050/1, EP/G036101/1, EP/M002438/1, EP/M001024/1), from the Royal Society Travel Exchange Grants 2012 and 2013 and from the Leverhulme Trust. A.W.D. acknowledges support from the National Science Foundation Graduate Research Fellowship Program (Grant DGF1106401).
Vol. 16 (8), pp. 4788–4791