CHARGE REDISTRIBUTION IN NONOHMIC HOPPING CONDUCTION IN DISORDERED MATERIALS

The spatial distribution of charge in a disordered medium is generally altered as steady-state flow is driven by progressively higher electr ic fields. Here a formalism to determine how the average site occupanc ies are altered by steady-state flow is described. An example is prese nted to illustrate when and how this charge redistribution differs fro m that obtained by replacing the hopping system by a set of unequal re sistors. The current carried by a low-density of charge carriers execu ting nearest-neighbor hopping along a disordered chain is calculated w ithout restricting the charge redistribution to that determined with t he resistor-network approximation.