The activation energy of hopping transport with sequential correlations of hops due to Coulomb interactions

The authors study the effects of correlations in successive jumps on the reduction of the activation energy epsilon 3 in impurity conduction at low concentrations. These correlation effects are considered within a mean-field theory, and a dielectric approach is used. They find that epsilon 3 is reduced by about 30% with respect to previous calculations that do not include relaxation. The new value is in better agreement with the experimental results and with Monte Carlo calculations by Nguyen and co-workers (1979). Their value for intermediate compensation still exceeds experimental values by about 50%.