Science / Medicine : Physicists Create ‘Atom Switch’

IBM scientists in San Jose have created an experimental switch in which a single atom hops back and forth across a tiny gap. The experiment could help in building atomic-sized electronic devices, physicists Donald Eigler, Christopher Lutz and William Rudge reported last week in the British journal Nature.

Such “atom switches” may one day be useful in making atomic-scale devices that store data or do computations in a computer, Lutz said. He added that nobody has shown whether the atom switches would offer advantages over other technologies. Serious obstacles also remain for producing a useful switch.

The group made their switch from a scanning tunneling microscope, which is normally used to produce images of atoms on surfaces. The microscope works by holding an extremely fine needle very close to a surface. To use this device as a switch, researchers lowered the needle until it was a few millionths of the width of a human hair above a surface of nickel atoms.

Researchers could then make a single atom of xenon jump repeatedly from the needle tip to the surface and back again, using bursts of current between the tip and the surface.