Dots image

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:

  1. 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.

  2. 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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  3. Last Modified: 02/01/03