IBM

By spelling out "IBM" in Xenon atoms on a nickel surface, Donald Eigler demonstrated the ability of a scanning tunneling microscope to pick up individual atoms and move them around.

A needle so tiny that its tip is a single atom moves across a surface in atomic-scale steps. A "tunneling current" flows between the needle and the surface. By measuring that current, a scanning tunneling microscope (STM) can form a picture of the surface that resolves individual atoms.

If all goes well, this year's Bethe lecturer will demonstrate the process to his Cornell University audience Oct. 19 by operating an STM over the Internet.

Donald M Eigler, an IBM fellow at the company's Almaden Research Center in San Jose, Calif., uses the STM to explore the physics of nanometer-scale structures and the applications of such structures to computing. Eigler will visit the Cornell campus next week to present the annual Hans Bethe lecture and lead two colloquia on physics at the nanometer scale.

In 1989, Eigler demonstrated the ability to manipulate individual atoms with a low-temperature STM, spelling out "I-B-M" with individual xenon atoms. Since then, his group's results include the invention of "quantum corrals," discovery of the "quantum mirage" effect, demonstration of a fundamentally new way to transport information through a solid, the demonstration of nanometer-scale logic circuits based on molecular cascades and demonstration of single-atom spin-flip spectroscopy.

The lecture, titled "Life Among the Atoms: A Celebration of the Small Frontier," will be presented at 7 p.m. Wednesday, Oct. 19, in Schwartz Auditorium, Rockefeller Hall. Eigler will describe how the microscope works, give some examples of how his research group uses it to broaden knowledge of the properties of small structures and, if the Internet connection works, present a live demonstration. The lecture is intended to be accessible to a nontechnical audience and is free and open to the public.

The first physics colloquium, at 4 p.m. Monday, Oct. 17, will deal with quantum computing. The second, on Monday, Oct. 24, will explain spin-excitation spectroscopy with the STM. The colloquia are intended for students and faculty.

The Bethe Lectures, established by the Cornell Department of Physics and the College of Arts and Sciences, honor the late Hans A. Bethe, Cornell professor emeritus of physics, whose description of the nuclear processes powering the sun won him a Nobel Prize in physics in 1967. The lectures have been given annually since 1977. Further information is available at http://www.physics.cornell.edu/physics/colloquia/bethe_lecture_2005.htm or from the physics department at 255-7561.