New phenomena in Josephson SINIS junctions.

Abstract

We analyze the dc and ac Josephson effects in ${S}_{a}{\mathrm{INIS}}_{b}$ junctions in which an additional bias current flows in the $N$ layer. The case of low temperatures and voltages $(eV,T\ensuremath{\ll}\ensuremath{\Delta})$ is considered in the dirty limit. We show that the critical Josephson current may change sign, and the considered SINIS junction may become a \ensuremath{\pi} junction if the voltage drop across the ${N/S}_{a}$ interface exceeds a certain value $({\mathrm{eV}}_{N}>\ensuremath{\Delta}/\sqrt{2})$. The ac Josephson effect may arise even if the current flows only through the ${N/S}_{a}$ interface, whereas the current through the ${S}_{b}/N$ interface is absent.