Magnetic-field-tuned superconductor-insulator transition in two-dimensional films

Abstract

A magnetic field is used to tune through a new superconducting-insulating transition of amorphous-composite indium oxide films at various stages of disorder. The results are in accord with scaling theory which identifies a universal sheet resistance separating a superconducting phase of localized vortices and Bose-condensed electron pairs from an insulating phase of Bose-condensed vortices and localized electron pairs. A unity dynamical exponent is confirmed and scaling behavior of the resistance over a wide range of temperatures and magnetic fields is found.