Confirmation of the universal conductivity critical exponent in a two-dimensional anisotropic system.

Abstract

Using a computer-controlled plotter, we have fabricated a well-defined two-dimensional anisotropic percolation system consisting of insulating random ellipsoids on a thin aluminum film. Measured conductivity exponents, t, for this anisotropic percolation system approach the same value as for the isotropic case near the critical region. We found that the universality concept that the critical exponents should be independent of the detailed microstructure is also valid for the anisotropic system. The measured percolation threshold for this anisotropic system is 0.330\ifmmode\pm\else\textpm\fi{}0.017, independent of the anisotropy ratio.