act31797@uxa.cso.uiuc.edu (<act31797@uxa.cso.uiuc.edu>) (04/08/90)
The following article, by Jon Van, was printed in the April 5 _Chicago_Tribune. SCIENTISTS LEARN HOW TO MOVE INDIVIDUAL ATOMS Scientists using the latest microscopic technology have found they can move individual atoms around a surface at will, a breakthrough that could have pro- found implications in the ultra-small world of electronics and even in indus- try. The ability to manipulate individual atoms opens the door for dramatic stride in building computer chips so complex and densely packed with components they could rival human brain cells in the amount of information they process and store. Using the new technique, scientists may someday be able to build transistors the size of molecules, packing 2 million times more hardware on a computer chip than is now possible. Smarter computer chips would bring many new practical applications for science and industry, add to the sophistication of today's generation of com- puters and hasten the day in which computers can do many intelligent tasks now performed by humans. Current chip technology is reaching the outer edges of sophistication and complexity, and scientists long have sought ways to break out of these limits. The capability to move atoms around freely might provide an answer to this problem. But there might be other applications, too. Humans might design and build new molecules never before seen in nature, perhaps yielding new mater- ials to suit any need--such as a material as flexible as rubber, tough as steel and light as plastic for making automobile bumpers. Scientists at IBM's Almaden Research Center in San Jose, Calif., reported the discovery Wednesday, demonstrating their power to the world by using indi- vidual atoms to spell out I-B-M. The discovery, reported in Thursday's issue of Nature, the British science journal, was made possible by a machine called the scanning tunnel microscope. That machine, developed in the early 1980's by IBM researchers in Switzerland, suspends the microscope's tip about an atom's width above the material to be studied. As the microscope's tip is moved back and forth across the surface, it rises and falls with the material's atomic surface, never quite touching it, while making a topographic map. The IBM scientists in California have used the tip to attract a single atom of xenon sitting on the surface of a nickel crystal and then to move the xenon to another spot on the surface. It took Donald Eigler and Erhard Schweizer about 22 hours to arrange 35 xenon atoms into a position to spell IBM, said Eigler, a physicist at the IBM lab in San Jose. He said each manipulation was something like moving a ping-pong ball over an egg carton's surface to get it into position. This is all done without actually touching the atom. After they put the atoms into position, they used the same microscope to record an image of the design. Eigler said he and Schweizer, a visiting scientist from the Fritz-Haber- Institut in Berlin, don't yet understand the physical force that allows them to move the atoms around. The work was done on a state-of-the-art scanning tunnel microscope and wouldn't have been possible on an earlier model, Eigler said. He designed and built the machine to do something altogether different: identify mole- cules by their inherent vibrational patterns. But instead, the scientists started working with xenon on an ultra-clean nickel crystal surface in a super-tight vacuum at a temperature of minus 453 degrees Fahrenheit, almost absolute zero, the temperature at which motion stops in all matter. As they studied the properties of xenon, a heavy gas used to fill elec- tronic flash tubes for photography and lasers, Eigler began thinking about interactions between individual atoms of xenon and the tungsten tip of his microscope. He decided to try manipulating atoms with it. Learning how to manipulate atoms one at a time so they could be used to build new molecules from scratch has long been a dream of materials scien- tists. While the accomplishment by Eigler and Schweizer moves science closer to that goal, practical applications apparently remain distant, Eigler said. After doing more xenon-and-nickel studies to learn what forces are at work, the researchers will try duplicating their work with other elements and would eventually like to build molecules from atoms using two different elements, he said. "For decades, the electronics industry has been facing the challenge of how to build smaller and smaller structures," he said. "For those of us who will now be using individual atoms as building blocks, the challenge will be how to build up structures atom by atom." Andrew Trapp act31797@uxa.cso.uiuc.edu