On the theory of hopping transport in strong electric fields

Abstract The familiar rate equation approach to hopping of electrons in disordered systems is based upon the concept of Anderson localization. Since localization can be strongly affected by high electric fields, we extend the rate equation approach by including off-diagonal components of the density matrix. For strong electron-phonon interaction, the off-diagonal components can be expressed explicitly in terms of the diagonal components, which allows a closed set of equations to be derived for the diagonal components.