THEORY OF INTERBAND TUNNELING IN CRYSTALS WITH IMPURITIES

A general theory is presented for the intraband and interband processes of electrons in a crystal with static impurities in a strong electric field. The interband tunneling processes, both the impurity-assisted and the Zener tunneling (and its modification by the impurities), are examined in detail. For the case of tunneling from a fully occupied band, the dependence of the tunneling rate on the electric field is shown in both cases to exhibit a steady term and some oscillatory terms, in agreement with recent experimental findings.