Nonlinear current-voltage characteristics of locally superconducting elemental films

Nonlinear I-V characteristics have been observed in quench-condensed films which are locally superconducting. We suggest an interpretation of an apparent threshold phenomenon in terms of the enhancement of conduction by the depinning of a charge structure that may characterize this insulating regime. We propose that this is a more likely description than Coulomb blockade or charge-anticharge unbinding phenomena.