DC Conductivity of a Random Barrier Network

Abstract

Abstract The current–voltage characteristics of a single potential barrier is highly nonlinear. The conductivity of a random barrier network is analyzed by extending the effective medium theory to the nonlinear case. Below the percolation threshold the conductivity shows nonlinear behaviour similar to the regular barrier network. Above the percolation threshold the conductivity is constant up to voltages comparable to the barrier height. In the ohmic region the activation energy of conductivity decreases when the fraction of barriers decreases. In the case of distributed barriers the activation energy decreases with decreasing temperature.