The scientist Richard Feynman suggested several decades ago that it would be possible to use single atoms to store bits of data. Researchers from the University of Wisconsin at Madison have taken a large step toward making the idea a reality with a prototype that uses single silicon atoms to represent the 1s and 0s of computing. Practical atomic-scale memory would increase the amount of information that could be stored per square inch of recording material by several thousand times. The researchers realized they had hit upon a mechanism for atomic memory when they discovered that scattering gold atoms on a silicon wafer caused the silicon atoms to assemble into tracks exactly five atoms wide. The pattern resembled the microstructure of a CD.
http://www.trnmag.com/Stories/2002/080702/Ultimate_memory_demoed_080702.html
