Dutch scientists have demonstrated controlling the motion of an atomic scale mechanical device, although whether more complex nanotech devices could be controlled by the mechanism at work here remains to be seen. Upon exposure to electrons from an STM tip, pairs of platinum atoms on a germanium surface can be made to pivot on one atom, swinging back and forth like a flipper on a pinball machine. From a Nanowerk Spotlight written by Michael Berger “Playing nanotechnology pinball in the atomic café“:
Functional nanomachinery will need to take into account the quantum effects that dominate the behavior of matter at the nanoscale, affecting the optical, electrical and magnetic behavior of materials.
Scientists in The Netherlands are now reporting how an atomic scale mechanical device consisting of two moving parts, each composed of only two atoms can be controlled by an external electrical signal, while being stable and providing a variety of functional modes. They jokingly refer to it as playing atomic pinball, since the two moving parts resemble the flippers in a pinball machine — unfortunately they haven’t got a ball yet to play with.
“We have demonstrated the stimulated and controllable mobility of an atomic scale mechanical device” Dr. Harold J.W. Zandvliet tells Nanowerk. “This atomic scale variant of pinball machine flippers exhibits a variety of dynamic modes that are exclusively excited by an external electrical signal. Our work is an important advance in atomic-scale engineering since it shows that even on the scale of a few atoms, a device can be constructed that only operates if an external stimulus is applied.”
…The scientists believe that the most likely explanation for the flipping dimer is that the substrate atom underneath the two revolving atoms has been replaced by a different atom, leading to a reduced binding of the dimers with the substrate and a sideways displacement of the dimers as they attach to neighboring substrate atoms.
The research was published in Nano Letters (abstract).