Issue
EPL
Volume 79, Number 5, September 2007
Article Number 57008
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/79/57008
Published online 06 August 2007
EPL, 79 (2007) 57008
DOI: 10.1209/0295-5075/79/57008

Proximity effect and multiple Andreev reflections in few-layer graphene

A. 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

bouchiat@lps.u-psud.fr

received 11 June 2007; accepted in final form 17 July 2007; published September 2007
published online 6 August 2007

Abstract
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 $2.5\,\mu {\rm m}$, 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 $2\Delta /{\rm e}$ (with $\Delta $ the superconducting gap of the electrodes), which persist up to fields of a few tesla.

PACS
73.23.-b - Electronic transport in mesoscopic systems .

© Europhysics Letters Association 2007