Localized phase-slip centers in proximity-induced long superconducting nanowires

摘要

Current-voltage (I-V) curves have been measured on 60-mu m-long Zn nanowires in contact with bulk film electrodes of Sn or Pb. The Zn nanowires become superconducting at the transition temperatures of the respectively electrodes, which are well above the transition temperature of bulk Zn. At temperatures well above the transition temperature of bulk Zn but below the transition temperatures of the electrodes, the I-V curves display a reproducible steplike pattern characteristic of the establishment of multiple localized phase-slip centers. The typical quasiparticle diffusion length associated with a phase-slip center is estimated to be 5-10 mu m. These results demonstrate that the observed proximity effect occurs along the entire length of a nanowire, rather than only at the nanowire-electrode interfaces.