Percolation in two-dimensional conductor-insulator networks with controllable anisotropy

Abstract

The conductivities of two-dimensional conductor-insulator networks generated photolithographically from laser speckle patterns have been measured. Isotropic networks with \ensuremath{\approx} 450 000 statistically independent units show a percolation threshold ${f}_{c}\ensuremath{\approx}41%$ conductor and a critical exponent $t\ensuremath{\approx}1.30$. Measurements on anisotropic networks and numerical simulations indicate that either ${f}_{c}$, $t$, or the size of the "asymptotic region" must vary with the degree of anisotropy.