THE CURRENT-VOLTAGE CHARACTERISTIC IN AN ULTRASMALL JUNCTION

The current-voltage characteristics of ultrasmall superconductor-insul ator-normal metal (S-I-N), and a superconductor-insulator-superconduct or (S-I-S) junctions are computed in the presence of a dissipative tra nsmission line. The amplitude of the discontinuous jump at the energy gap of a single-particle current is greatly influenced by the size of the capacitance and the impedance of the external transmission line in the small junction. The results agree with Ambegaokar-Baratoff in the limit of vanishing impedance of a transmission line or large junction capacitance. (C) 1997 Academic Press Limited.