Subharmonic Shapiro steps and assisted tunneling in superconducting point contacts
Superconductivity
2009-11-07 v1 Mesoscale and Nanoscale Physics
Abstract
We analyze the current in a superconducting point contact of arbitrary transmission in the presence of a microwave radiation. The interplay between the ac Josephson current and the microwave signal gives rise to Shapiro steps at voltages V = (m/n) \hbar \omega_r/2e, where n,m are integer numbers and \omega_r is the radiation frequency. The subharmonic steps (n different from 1) are a consequence of the ocurrence of multiple Andreev reflections (MAR) and provide an unambiguous signature of the peculiar ac Josephson effect at high transmission. Moreover, the dc current exhibits a rich subgap structure due to photon-assisted MARs.
Keywords
Cite
@article{arxiv.cond-mat/0109152,
title = {Subharmonic Shapiro steps and assisted tunneling in superconducting point contacts},
author = {J. C. Cuevas and J. Heurich and A. Martin-Rodero and A. Levy Yeyati and G. Schoen},
journal= {arXiv preprint arXiv:cond-mat/0109152},
year = {2009}
}
Comments
Revtex, 4 pages, 4 figures