Moving Atoms One by One

`PEACE 91'' may sound like an antiwar slogan. But when scientists at the Hitachi Central Research Laboratories in Toyko wrote it in letters less than 1.5 billionths of a meter (1-1/2 nanometers) high, they were celebrating the future of an emerging technology that promises to produce useful products by manipulating materials one atom at a time. This follows the work of Donald Eigler and E. K. Schweizer at the International Business Machines Corporation's Almaden Research Center in San Jose, Calif. Last April, they arranged 35 xenon atoms to spell out the company logo on a nickel crystal.

The tool that manipulates the atoms is the scanning tunneling microscope (STM) - an invention for which Gerd Binnig and Heinrich Rohrer of IBM's Zurich research laboratory won a 1986 Nobel prize. ``Tunneling'' refers to the nature of the electric current by which an STM senses atomic topography. Dr. Binnig and others also are developing the atomic force microscope (AFM), which uses force rather than current to trace that topography.

AFMs have produced many stunning pictures of atomic arrangements. But the processes that let them sense atoms also enable them to manipulate atoms. Many laboratories are learning to use these processes to open up the new field of nanotechnology, which promises to build electronic devices on the scale of nanometers. Such devices could become practical by the end of this decade.

Research progress is rapid. The IBM team took 22 hours to write three letters. But recently in Germany, Harald Fuchs of BASF in Ludwigshafen and Thomas Schimmel at the University of Bayreuth have built triangular structures of three atoms each on a tungsten diselenide crystal surface at room temperature in air in fractions of a second. Last month, the US National Institute of Standards and Technology announced a room-temperature procedure for manipulating atoms and molecules on surfaces.

Surface scientist Sau Lan Taug at Du Pont's Central Research and Development facility in Wilmington, Del., says nanotechnology ``opens up possibilities for applications limited only by one's imagination.''