Noise-induced switching dynamics of bistable electronic transport systems. June 25, 2013
Invited Lectures ; Stephen Teitsworth ; This talk reviews our recent experimental and theoretical work to understand the dynamics of noise-induced switching between co-existing metastable states of nonlinear electronic transport systems. Such bistability is generally associated with the presence of negative differential resistance elements for which an increasing applied voltage produces a decreasing electrical current. Two prototypical examples of this behavior are provided by the tunnel diode (TD) and the semiconductor superlattice (SL), both of which are subject to the intrinsic electronic shot noise arising from the discrete nature of charge. Using a novel high bandwidth technique, we have measured switching time distributions in both of these systems over a wide range of time scales and confirm predicted exponential distributions for the TD system. However, for the SL system, the distributions exhibit unexpected power law decay at long times, behavior that is likely due to small levels of structural disorder in that system. Furthermore, measured mean switching times exhibit interesting scaling behavior as a function of applied voltage in the neighborhood of a value corresponding to a saddle-node bifurcation. A useful theoretical model for the TD system takes the form a three-dimensional stochastic dynamical system which allows the prediction of switching time distributions as well as most probable transition paths.
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University of Bielefeld, Germany