Danish scientists have created a chip where a single atom jumping back and forth could generate the binary code which is the basis of digital information used by computers. Applying this technique - which might only become commercially viable in a decade or two - information stored today on one million CD-Roms could be stored on a single disc.

Using a scanning-tunnelling microscope, a four-man team at the microelectronics centre of the Danish University of Technology was able to remove from a hydrogen layer surface on a silicon chip - standard in modern computers - one of a pair of hydrogen atoms attached to one silicon atom, leaving the remaining hydrogen atom jumping back and forth.

Team leader, Dr Francois Grey said: "This shows you can do it with the material in a controlled way." He noted the experiment had been completed successfully at normal room temperature.

Scientists elsewhere have conducted similar experiments making single atoms jump back and forth, but their work was done with material frozen to near absolute zero temperature. Dr Grey said the Danish team was the first to have succeeded in room temperature. His team removed the hydrogen atom in an ultra-high vacuum chamber to keep the surface absolutely clean.