Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, April 5, 1990 TAG: 9004041170
SECTION: NATIONAL/INTERNATIONAL PAGE: A1 EDITION: STATE
SOURCE: Los Angeles Times
DATELINE: LENGTH: Medium
Among other things, ultraminiaturized electronic components could allow researchers to build microcomputers that operate hundreds to thousands of times faster than the fastest supercomputers available today and that store data at densities almost undreamed of now.
The technique should also provide new understanding of the so-called surface catalysts that are used in making as much as 85 percent of the products of the petrochemical industry.
The researchers report in today's issue of Nature that they manipulated the atoms using an expensive, custom-built scanning tunneling microscope, which is so sensitive that it must be shielded from body heat and the voices of people in the same room.
Their prize specimen: 35 xenon atoms painstakingly arranged over a 22-hour period to spell out "IBM" in letters that are one five-hundred-thousandth the size of letters on most newspaper pages.
But physicists Donald M. Eigler and Erhard K. Schweizer of IBM's Almaden Research Center in San Jose, Calif., foresee far more practical applications for their technique. They noted that it should be possible to modify or assemble certain molecules by the technique, especially molecules that are otherwise unobtainable.
Manufacturers of synthetic rubber, for example, might be able to use catalysts composed of clusters of two or three metal atoms to produce highly specialized materials. Such clusters are very difficult to produce by chemical reactions, but might be made easily with the new technique.
Physicist Sheldon Schultz of the University of California, San Diego, called the work "a real contribution." The IBM researchers, he said, have "demonstrated the ability to place atoms with atomic precision. It's the first time it has been done anywhere near that level. . . .
The scanning tunneling microscope was invented in the early 1980s by physicists Gerd Binnig and Heinrich Rohrer of IBM's Zurich Research Laboratory in Switzerland, a feat for which they won the 1986 Nobel Prize for physics.
The device works in a manner similar to a phonograph. An extremely small needle, whose tip is formed by a single atom, passes over the surface of an object in a regular pattern. A principle of physics called the tunneling effect keeps the tip of the needle a precise distance from the surface.
As the tip moves up and down to follow the contours of the object, sensitive electronics measure its motion and convert that information into a detailed picture of the surface. Th e microscope can "see" objects as small as a single atom.
Eigler and Schweizer, who was a visiting scientist from the Fritz Haber Institut in West Germany when the work was done in November of last year, found that by placing the tip closer to a surface atom than normal, they could drag the atom along with the tip as they moved it.
Eigler said in a telephone interview that he thinks that electrostatic attraction caused the atom to follow the tip until electrical current through the tip is reduced, but that they are doing further studies to show precisely how the phenomenon occurs.
"We've made educated guesses about what the mechanism was," he said. "Now, we are trying to go beyond guesses to the point of hard science."
by CNB