Effect of two-impurity tunnel resonance on the lower critical field of a long S-I-S tunneling contact with weak structural disorder in the I layer
The region where the effect of two-impurity quantum resonance-percolation trajectories (QRPTs) [1] on the lower critical field value of a disordered S-I-S (superconductor-insulator-superconductor) contact predominates is found on the (μ — ɛ0, c) parameter plane, where μ is the contact Fermi level, ɛ0 is the energy of the single-impurity local electron level, and c is the density of impurities in the I layer. The crossover line between the regions where the effect of single-impurity and two-impurity QRPTs predominates is plotted. The contribution from two-impurity QRPTs to mesoscopic fluctuations of the lower critical field of a disordered S-I-S contact is studied.