Critical behavior of the weakly nonlinear conductivity and flicker noise of two-component composites.
Critical behavior of the weakly nonlinear conductivity and flicker noise of two-component composites.
复制标题
双组分复合材料弱非线性电导率和闪烁噪声的临界行为。
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
Bergman
中科院分区：
文献类型：
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作者：
Lévy;Bergman
建立了双组分复合材料渗流阈值附近的弱非线性电导和闪变噪声的标度理论，并讨论了它的一些物理结果。我们假定这两个组分的欧姆电导率都是有限的，但两者的欧姆电导率之比与1相差很大。我们预测，在某些条件下，弱非线性电导率与良导体的体积分数存在非单调的依赖关系，极大值非常接近阈值，局部极小值略高于阈值。我们还预测，根据系统重要物理参数的取值，无论是良导体还是劣导体，在阈值以上和阈值以下都可能主导临界行为。其中一些预测与二维随机电阻网络的数值模拟结果和有效介质近似(EMA)进行了比较。数值结果重现了标度理论的一些预言。EMA表现出了相同的定性行为，但对定量结果的重现性很差。
A scaling theory of the weakly nonlinear conductivity and flicker noise near the percolation threshold of a two-component composite is formulated and some of its physical consequences are examined. Both components are assumed to have finite Ohmic conductivities, but with a ratio that is very different from 1. We predict that under certain conditions a nonmonotonic dependence of the weakly nonlinear conductivity on the volume fraction of the good conductor can be observed, with a maximum very near to the threshold and a local minimum somewhat above it. We also predict that, depending on the values of the important physical parameters of the system, either the good conductor or the poor conductor may dominate the critical behavior both above and below the threshold. Some of these predictions are compared with results of numerical simulations on two-dimensional random resistor networks and with an effective-medium approximation (EMA). The numerical results are shown to reproduce some of the predictions of the scaling theory. The EMA is shown to follow the same qualitative behavior but to reproduce poorly the quantitative results.