Effective Medium Approximation for Nonlinear Conductivity of a Composite Medium
Bruggeman’s Self-Consistent Effective Medium Approximation for the linear conductivity of a composite medium is reformulated in a manner such that the averaging procedure that must be used becomes unambiguous. The new formulation can be applied equally unambiguously to nonlinear conductivity in a composite medium. It is used to construct a Bruggeman-type approximation for a strong, power law nonlinear conductivity, and the scaling form of this approximation in the vicinity of a percolation threshold is found. It is also used to construct such an approximation for the small power-law-nonlinearity correction term in a composite conductor whose leading behavior is linear. In this case the Bruggeman-type approximation becomes useless long before the percolation threshold is reached. The reasons for this are discussed.
KeywordsPercolation Threshold Leading Behavior Local Electric Field Composite Medium Composite Conductor
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- D. Stroud and F. P. Pan, Phys. Rev. B20(1979), 455–465.Google Scholar
- I. Webman, J. Jortner and M. H. Cohen, Phys. Rev. B16(1977), 2959–2964.Google Scholar
- D. J. Bergman, Phys. Rev. B39(1989), 4598–4609.Google Scholar
- D. Stroud and P. M. Hui, Phys. Rev. B37(1988), 8719–8724.Google Scholar
- G. Milton in Physics and Chemistry of Porous Media, eds. D. L. Johnson and P. N. Sen, AIP Conf. Proc. No. 107, New York, 1984, pp. 66–77.Google Scholar