The response of a mesoscopic homogeneous superconducting wire, connected with bulk normal metal reservoirs, is investigated theoretically as a function of the applied voltage. We found both symmetric and asymmetric states which are characterized by a stationary symmetric and asymmetric distribution of the order parameter with respect to the center of the wire. For wires with length $L$ of about the relaxation length of the nonequilibrium quasiparticle distribution function $\overline{L_E}$, the asymmetric superconducting state survives up to higher values of the voltage than the symmetric one and may exist both in the voltage- and the current-driven regimes.

• Received 23 October 2006

DOI:https://doi.org/10.1103/PhysRevB.75.104515