I.B.M. scientists have measured the force needed to nudge one atom. About one-130-millionth of an ounce of force pushes a cobalt atom across a smooth, flat piece of platinum. Pushing the same atom along a copper surface is easier, just one-1,600-millionth of an ounce of force. The scientists report these minuscule findings in Friday’s issue of the journal Science. I.B.M. scientists have been pushing atoms around for some time, since Donald M. Eigler of the company’s Almaden Research Center in San Jose, Calif., spelled ‘IBM’ using 35 xenon atoms in 1989. Since then, researchers at the company have continued to explore how they might be able to construct structures and electronic components out of individual atoms. Knowing the precise forces required to move atoms ‘helps us to understand what is possible and what is not possible,’ said Andreas J. Heinrich, a physicist at Almaden and an author of the new Science paper. ‘It’s a stepping stone for us, but it’s by no means the end goal.’ In the experiment, Dr. Heinrich and his collaborators at Almaden and the University of Regensburg in Germany used the sharp tip of an atomic force microscope to push […]