Contributing Editor's Note: The theoretical
modeling of such devices invokes many ideas from quantum chaos.
See, for example, Comdig
2001.35.8. In particular, Jahn-Teller theory plays an
important role.
Most of these theoretical models have been used to study
systems simpler than the actual experimental devices discussed in
the article, so there is considerable room for theoretical work in
the modeling of nanomechanical devices.
Excerpts: (...) A long-sought goal of scientists has
been to shrink the transistor, the basic building block of
electronic circuits, to smaller and smaller size scales.
Scientists at Cornell University have now reached the smallest
possible limit: a transistor in which electrons flow through a
single atom.
The Cornell researchers have created a single-atom transistor
by implanting a "designer" molecule between two gold electrodes,
or wires, to create a circuit. When voltage was applied to the
transistor, electrons flowed through a single cobalt atom within
the molecule. (...)
McEuen cautions that the device cannot yet be described as
having all the functions of a traditional transistor, such as
amplification. But he sees a potential application for the new
transistor as a chemical sensor because a change in the
environment around the molecule could cause a measurable
alteration of the conductance of the device. (...)
