Study on cantilever NEMS switches appears in Nature Communications
Stochastic switching of cantilever motion
Nanoscale mechanical switches can utilize the noise from their environment to detect small signals. This is demonstrated by researchers at the Kavli Institute of Nanoscience at the TU Delft in an article which appeared in Nature Communications on 31 October.
In engineering, noise and nonlinear behaviour are in general unwanted and tend to be avoided. The article demonstrates how these features can be exploited beneficially in nanoscale mechanical systems. The researchers performed experiments with tiny ultra-flexible springboards, known as cantilevers. Cantilevers play an important role in instruments for the imaging and manipulation of objects at nanometer scale.
The phenomenon demonstrated in the cantilevers is referred to as stochastic resonance. In this counterintuitive process, increasing the noise leads to an improved signal transmission. Stochastic resonance is frequently encountered in biological systems, like neural networks.
Stochastic resonance can occur in ultra-flexible cantilevers due to their low spring stiffness. This results in nonlinear behaviour, and a strong sensitivity to fluctuations.. At large amplitudes, the vibrations become bi-stable. In a bi-stable system, noise can facilitate transitions between stable states: stochastic resonance.
The authors argue that specific ultrathin nanomechanical devices at room temperature never behave as a linear system,. This calls for new measuring techniques, which involve probabilities and switching rates rather than the deterministic input-output relations of present-day transducers.
Stochastic switching of cantilever motion, W.J. Venstra, H.J.R. Westra, H.S.J. van der Zant, Nature Communications 4 | Article number: 2624 | doi:10.1038/ncomms3624 | Published 31 October 2013.
This work is funded by the European Union’s Seventh Framework Programme (FP7/2007-2013) under Grant Agreement no. 318287, project LANDAUER.