Possibility of macroscopic resonant tunneling near the superconductor-insulator transition in YBa2Cu3O7 − δ thin films

Experimental results of the I-V characteristics near the superconductor-insulator transition observed for disorder-tuned YBa2Cu3O7 − δ thin films are presented. The I-V characteristics exhibit new quasiperiodic structures as a function of the current. The current interval, the number of the dI/dV peaks, and the magnetic-field dependence of the peaks are consistent with the theoretical predictions of the resonant tunneling of a phase particle in a tilted-cosine potential for a single Josephson junction with small capacitance.