Giving electrons a ride: nanomechanical electron shuttles

In 1998, L.Y. Gorelik et al., proposed a novel mechanism of charge transport in nanostructures based on mechanical shuttling of electrons

Fig. 1

. The basic element (see Fig. a,b), which is called a shuttle-junction, consists of a metallic nanoparticle connected by flexible, “elastic” molecules to two nanoelectrodes. For low applied voltages where the nanoparticle is stationary the device is similar to a single-electron transistor. The vibrational process can be initiated by applying a sufficiently large bias voltage to the electrodes and nanoparticle start to shuttle electrons between electrodes (see self-explanatory animations: http://www.lboro.ac.uk/departments/ph/research/animations/Shuttle1.swf). Exploitation of this mechanism could potentially lead to the development of a new generation of nanomechanical electronic devices, such as transistors, current standards, very sensitive electrometers, sensors, logic gates, and memories with ultra low power consumption and high speed of operation.

Due to recent fruitful collaboration [1] between Loughborough and Bath Universities, the first metallic electromechanical nanoshuttles consisting of a 20 nm diameter gold nanoparticle embedded within the gap between two gold electrodes (Fig. c) was fabricated. Current-voltage characteristics for these devices have been measured and compared with the results of our computer simulations.

1. A.V. Moskalenko, S.N. Gordeev, O.F. Koentjoro, P.R. Raithby, Robert.W. French, F. Marken, and S.E. Savel'ev, Phys. Rev. B 79, 241403(R) (2009);  http://link.aps.org/abstract/PRB/v79/e241403

Theoretical model of an idealised shuttle-junction (a), illustration of the shuttling process (b) and (c) experimental realisation of a shuttle-junction. The device consists of a 20 nm gold nanoparticle attached to two gold electrodes through monolayers of octanedithiol molecules serving as springs.