Experimental evidence for a collective insulating state in two-dimensional superconductors.
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.
Sambandamurthy
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G
Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
Engel
L W
LW
Johansson
A
A
Peled
E
E
Shahar
D
D