Proximity Effect and Multiple Andreev Reflections in Gold Atomic Contacts

E. Scheer; W. Belzig; Y. Naveh; M. H. Devoret; D. Esteve; C. Urbina

doi:10.1103/PhysRevLett.86.284

Proximity Effect and Multiple Andreev Reflections in Gold Atomic Contacts

E. Scheer, W. Belzig, Y. Naveh, M. H. Devoret, D. Esteve, and C. Urbina

Phys. Rev. Lett. 86, 284 – Published 8 January 2001

Abstract

We investigate the electronic transport properties of gold point contacts with superconducting aluminum leads. The modifications induced by the proximity effect in the quasiparticle density of states at the contact region are measured by tunnel spectroscopy. The theory of transport through multiple Andreev reflections is extended to incorporate these effects and used to determine the number and transmission coefficients of the conduction channels in the contact regime. We find that the smallest contacts, formed by one gold atom between the electrodes, contribute one single channel to the transport with variable transmission $T$ between 0.1 and 1.

Received 9 March 2000

DOI:https://doi.org/10.1103/PhysRevLett.86.284

Authors & Affiliations

E. Scheer^1,*, W. Belzig², Y. Naveh^3,†, M. H. Devoret⁴, D. Esteve⁴, and C. Urbina⁴

¹Physikalisches Institut, Universität Karlsruhe, D-76128 Karlsruhe, Germany
²Department of Applied Physics, Delft University of Technology, 2600 GA Delft, The Netherlands
³Department of Physics, State University of New York at Stony Brook, Stony Brook, New York 11794
⁴Service de Physique de l'Etat Condensé, Commissariat à l'Energie Atomique, Saclay, F-91191 Gif-sur-Yvette Cedex, France

^*Present address: Fachbereich Physik, Universität Konstanz, D-78457 Konstanz, Germany. Electronic address: Elke.Scheer@uni-konstanz.de
^†Present address: IBM Research Labs in Haifa, MATAM, Haifa 31905, Israel.