title: Experimental evidence for a collective insulating state in two-dimensional superconductors.
abstract: We present the results of an experimental study of the current-voltage characteristics in a strong magnetic field (B) of disordered, superconducting, thin films of amorphous indium oxide. As the B strength is increased superconductivity degrades, until a critical field (B(c)) where the system is forced into an insulating state. We show that the differential conductance measured in the insulating phase vanishes abruptly below a well-defined temperature, resulting in a clear threshold for conduction. Our results indicate that a new collective state emerges in two-dimensional superconductors at high B.
authors.affiliation: Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: G
authors.initials: G
authors.lastname: Sambandamurthy
authors.forename: L W
authors.initials: LW
authors.lastname: Engel
authors.forename: A
authors.initials: A
authors.lastname: Johansson
authors.forename: E
authors.initials: E
authors.lastname: Peled
authors.forename: D
authors.initials: D
authors.lastname: Shahar