Percolation in metal-insulator composites of randomly packed spherocylindrical nanoparticles

Article

关键词: MOLECULAR-DYNAMICS SIMULATIONS;    DISPERSED IONIC CONDUCTORS;    EPITAXIAL-GROWTH;    CONDUCTIVITY;    DIFFUSION;    EXPONENTS;    CLUSTERS;    RELEASE;    MODEL;   

DOI  :  10.1103/PhysRevB.103.134110

来源: SCIE

【 摘 要 】

While classical percolation is well understood, percolation effects in randomly packed or jammed structures are much less explored. Here we investigate both experimentally and theoretically the electrical percolation in a binary composite system of disordered spherocylinders, to identify the relation between structural (percolation) and functional properties of nanocomposites. Experimentally, we determine the percolation threshold p(c) and the conductivity critical exponent t for composites of conducting (CrO2) and insulating (Cr2O3) rodlike nanoparticles that are nominally geometrically identical, yielding p(c) = 0.305 +/- 0.026 and t = 2.52 +/- 0.03 respectively. Simulations and modeling are implemented through a combination of the mechanical contraction method and a variant of random walk (de Gennes ant) approach, in which charge diffusion is correlated with the system conductivity via the Nernst-Einstein relation. The percolation threshold and critical exponents identified through finite-size scaling are in good agreement with the experimental values. Curiously, the calculated percolation threshold for spherocylinders with an aspect ratio of 6.5, p(c) = 0.312 +/- 0.002, is very close (within numerical errors) to the one found previously in two other distinct systems of disordered jammed spheres and simple cubic lattice, an intriguing and surprising result.

【 授权许可】

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