Superconductivity-Related Insulating Behavior

Abstract

We present the results of an experimental study of superconducting, disordered, thin films of amorphous indium oxide. These films can be driven from the superconducting phase to a reentrant insulating state by the application of a perpendicular magnetic field ($B$). We find that the high-$B$ insulator exhibits activated transport with a characteristic temperature, $T_I$. $T_I$ has a maximum value ($T_I^p$) that is close to the superconducting transition temperature ($T_c$) at $B=0$, suggesting a possible relation between the conduction mechanisms in the superconducting and insulating phases. $T_I^p$ and $T_c$ display opposite dependences on the disorder strength.