Resonant electron tunneling through double-degenerate local state with account of strong electron–phonon interaction

In an approach of low transparency of barrier the tunneling of electrons has been considered with an account of Coulomb and electron–phonon interactions in a local state. The local state in potential barrier is supposed to be double degenerate. It is shown that in the case of weak electron–phonon and strong electron–electron interactions the dependence of tunneling current on applied voltage has a step-like character at low temperatures, and in a region of small applied bias there is a threshold value. In the region of big applied bias the bistable state of the tunneling is possible. In the alternative case of strong electron–phonon and weak electron–electron interactions the threshold of tunneling current can already be bistable.