Tiny wires trigger electric reversal

1:41pm, March 28, 2006

From Baltimore, at a meeting of the American Physical Society

Physicists have observed an unexpected reversal of conductive behavior in ultracold, ultrathin zinc wires.

Typically, a metal wire more readily superconducts, or transports electricity without resistance, when it spans superconductive electrodes. However, that wire loses its superconductivity if strung between electrodes of normal metals.

Yet in recent experiments, ultrathin zinc wires did just the opposite: They conducted normally when between superconductive electrodes but became superconductive when between normal electrodes.

The reversal is "very stunning, very surprising," says theoretical physicist Dung-Hai Lee of the University of California, Berkeley.

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