Nonlinear dc response in composites: A percolative study

The dc response, namely the I-V and G-V characteristics, of a variety of composite materials are in general found to be nonlinear. We attempt to understand the generic nature of the response characteristics and study the peculiarities associated with them. Our approach is based on a simple and minimal bond percolative network model. We do simulate the resistor network with appropriate linear and nonlinear bonds and obtain macroscopic nonlinear-response characteristics. We discuss the associated physics. An effective-medium approximation of the corresponding resistor network is also given.