The problem of impurity conduction at moderate compensation has been treated using the concept of multielectron single-phonon transitions. The problem was treated in the region of density, temperature, and compensation where two- (or many-) electron transitions begin to be important. A compensation of 0.5 is used with a temperature range of 1 to 5 K and an average majority impurity separation of 200 to 600 Å in germanium. The problem is treated by comparing the transition rates of one- and multielectron transitions of the localized electron system where the one-electron transition defines the critical impedance in a percolation path at low densities and high temperatures. It is found that two- and three-electron effects may account for the lowering of the "activation energy" seen experimentally as the density of impurities is raised. Comparison to currently available experimental data is made.

• Received 30 March 1973

DOI:https://doi.org/10.1103/PhysRevB.9.664