Metallic Dots
A wide variety of disordered systems exhibit threshold behavior and
nonlinear response to an applied drive. One such system is charge
transport through metallic dot arrays, such as, for example, through
triangular monolayers of gold nanocrystals. In models of randomly charged
dots separated by tunnel barriers, threshold behavior and scaling of
the current-voltage curves are found. Experimentally, a wide range
of scaling exponents appear. This may be related to the different
effective dimensionality of the experimental systems.
We have also considered the effects of systematically disordering our
2D arrays by the addition of voids where charge cannot flow.
In this case a simple power-law scaling is lost which agrees well
with the recent experiments of Heinrich Jaeger's group at the
University of Chicago,
R. Parthasarathy, X-M Lin, and H.M. Jaeger Phys. Rev. Lett 87, 186807 (2001).
Papers:
-
Charge transport transitions and scaling in disordered arrays of
metallic dots
C. Reichhardt and C.J. Olson Reichhardt
online version
Physical Review Letters 90 046802 (2003).
We examine the charge transport through disordered arrays of metallic
dots using numerical simulations. We find power law scaling in the
current-voltage curves for arrays containing no voids, while for void-filled
arrays charge bottlenecks form and a single scaling is absent, in agreement
with recent experiments. In the void-free case we also show that the
scaling exponent depends on the effective dimensionality of the
system. For increasing applied drives we find a transition from
2D disordered filamentary flow near threshold to a 1D smectic flow which
can be identified experimentally using characteristics in the
transport curves and conduction noise.
-
Temperature and ac effects on charge transport in metallic arrays
of
dots
C. Reichhardt and C.J. Olson Reichhardt
online version
Phys. Rev. B 68 165304 (2003).
Links to groups working on transport through nanodots:
Heinrich Jaeger's group
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Last Modified: 02/01/03