Absolute negative resistance of a tunnel contact between superconductors with a nonequilibrium quasiparticle distribution function
Gershenzon M. E., Falei M. I.
Experiments reveal that the resistance of a tunnel junction between superconductors goes negative when excess quasiparticles are excited in the electrode having the larger energy gap Δ{. This effect occurs at bias voltages I V\ ^ (Δι — Δ2)/β, where Δ, and Δ2 are the values of the energy gap in the superconducting electrodes.