Direct Measurement of the Josephson Supercurrent in an Ultrasmall Josephson Junction

A. Steinbach; P. Joyez; A. Cottet; D. Esteve; M. H. Devoret; M. E. Huber; John M. Martinis

doi:10.1103/PhysRevLett.87.137003

Direct Measurement of the Josephson Supercurrent in an Ultrasmall Josephson Junction

A. Steinbach, P. Joyez, A. Cottet, D. Esteve, M. H. Devoret, M. E. Huber, and John M. Martinis

Phys. Rev. Lett. 87, 137003 – Published 10 September 2001

Abstract

We have measured the supercurrent flowing through a nonhysteretic, ultrasmall, voltage-biased Josephson junction. In contrast with experiments performed so far on hysteretic Josephson junctions, we find a supercurrent peak whose maximum $I_{s \max}$ increases as the temperature $T$ decreases. The asymptotic $T = 0$ value of $I_{s \max}$ agrees with the junction Ambegaokar-Baratoff critical current, as predicted by theory.

Received 10 April 2001

DOI:https://doi.org/10.1103/PhysRevLett.87.137003

Authors & Affiliations

A. Steinbach¹, P. Joyez¹, A. Cottet¹, D. Esteve¹, M. H. Devoret¹, M. E. Huber², and John M. Martinis³

¹Service de Physique de l'Etat Condensé, CEA-Saclay, F-91191 Gif-sur-Yvette, France
²Department of Physics, University of Colorado at Denver, Denver, Colorado 80217
³National Institute of Standards and Technology, Boulder, Colorado 80303