Proximity effect and multiple Andreev reflections in few-layer grapheneA. Shailos1, W. Nativel2, A. Kasumov1, C. Collet2, M. Ferrier1, S. Guéron1, R. Deblock1 and H. Bouchiat1
1 Université Paris-Sud, CNRS, UMR 8502 - F-91405 Orsay Cedex, France
2 Thales Research and Technology - F-91767 Palaiseau Cedex, France
received 11 June 2007; accepted in final form 17 July 2007; published September 2007
published online 6 August 2007
We have investigated electronic transport of few-layer graphene (FLG) connected to superconducting electrodes. The device is prepared by mechanical exfoliation of graphite. A small mesa of FLG is connected to two tungsten electrodes, separated by , grown by focused ion beam. Whereas the tungsten electrodes are superconducting below 4 K, the proximity effect in FLG develops below 1 K, and is characterized by a factor 2 differential resistance drop at low bias. We find multiple Andreev reflection peaks at voltages corresponding to submultiples of (with the superconducting gap of the electrodes), which persist up to fields of a few tesla.
73.23.-b - Electronic transport in mesoscopic systems .
© Europhysics Letters Association 2007