Tunnelling electrons nano-motor

Nature contains a wide range of nanomotors — for example, some bacteria and other tiny organisms propel themselves using whip-like structures that are driven by biomolecular motors. Not surprisingly, researchers are looking at such “biomotors” for inspiration.

Powered by tunneling electrons
The quantum-mechanical tunnelling of protons is believed to be at the heart of some biomotors, and now Petr Král and colleagues that the University of Illinois at Chicago have shown that electron tunnelling could be used to drive manmade nanomotors.

The team used molecular-dynamics computer simulations to model nanomotors that comprise a carbon nanotube shaft with molecular "stalks" terminated by conducting "blades" (see figure). The rotor resembles a water wheel, except that one electron at a time tunnels between stationary electrodes and moving blades.

With each electron passing through the blades, the device rotates by either 120° or 60° — depending on how the blades are configured. Rotation occurs because the net effect of charging and discharging the blades nearest to the electrodes creates an electrode dipole moment across the rotor. This dipole is subject to the electric field created by the two oppositely-charged electrodes and the resulting torque drives the rotor.

http://nanotechweb.org/cws/article/tech/36611;jsessionid=AA00ABFFF75D0344F557B783FEEEF543