Radiation Effects in Cooper Pair Insulating Thin Films

摘要

Cooper-pair insulators are materials that exhibit superconducting behavior, but under specific conditions, regarding film thickness, bias voltage, applied magnetic field, and presence of magnetic impurities, act as insulators with thermally activated Cooper pairs as charge carriers. This paper investigates possible radiation effects in thin films of such materials. Radiation effects are predicted on the basis of Monte Carlo simulations, using 2D Josephson junction array as a model of material structure. Results of a combined theoretical and numerical analysis suggest that radiation-induced change of the Josephson junction charging energy could significantly affect the current-voltage characteristics of a Cooper-pair insulator, and that a transition to a metallic state is possible, due to radiation-induced disruption of the fine-tuned granular structure. The breaking of Cooper pairs, caused by incident and displaced ions, can also destroy the conditions for this specific insulating state to exist.