Abstract:
We report on measurements of first-passage-time distributions associated with current switching in
weakly coupled GaAs/AlAs superlattices driven by shot noise, a system that is both far from equilibrium
and high dimensional. Static current-voltage (I-V) characteristics exhibit multiple current branches and
bistability; precision, high-bandwidth current switching data are collected in response to steps in the applied
voltage to final voltages near the end of a current branch. For a range of voltage values, the measured switching
times vary stochastically. At short times, the switching time distributions decay exponentially,
while at longer times the distributions develop nonexponential tails that follow an approximate power law
over several decades. The power law decay behavior is attributed to the presence of multiple switching
pathways, which may arise from small spatial variations in the superlattice growth parameters.
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