Atomic switch for nanoscale devices moves closer to reality

Atomic switch for nanoscale devices moves closer to reality

Using a beam of electrons from a scanning tunneling microscope (STM), researchers at the National Institute of Standards and Technology (Gaithersburg, MD) were able to move a single atom in a small molecule back and forth between two positions on a crystal surface. These findings represent a significant step toward the development of an atomic switch that would turn electrical signals on and off in nanoscale devices.

A computer-generated spatial map of the atom switching speed and probability shows that switching is most likely when the STM tip is positioned to the left of the cobalt atom (blue and white speckled area).

During the experiments, a molecular chain of one cobalt atom and several copper atoms set upon a surface of copper atoms was constructed. Researchers analyzed the effects on atom-switching rate as changes occurred in the STM voltage and in the current between the STM tip and surface. Above 15 to 20 mV, the probability for switching per electron is constant, with higher currents resulting in faster switching.

These findings can also be applied to nanoscale fabrication on semiconductors and insulating films to enable the development of new classes of electronic and magnetic devices constructed atom by atom. For more information, visit http://www.nist.gov/public_affairs/releases/atomic_switch.htm.

Ralph Raiola