RESONANT-TUNNELING IN THE PRESENCE OF A 2-LEVEL FLUCTUATOR - AVERAGE TRANSPARENCY

We consider electrons tunneling through a double-barrier resonant-tunn eling structure (DBRTS) and interacting with a defect which has intern al degrees of freedom. Usually such a defect has two (or more) metasta ble configurations and can switch between them due to its interaction with a thermal bath. Interaction between the tunneling electron and th e dynamic defect creates a noisy environment surrounding the DBRTS, an d leads to fluctuations in time of the resonant level. Such fluctuatio ns result in inelastic tunneling and low-frequency noise. This paper i s focused on the problem of inelastic resonant tunneling. We have calc ulated the average transparency for various relations between the swit ching rate of the dynamic defect, the escape rate of the electron from the resonant level in the well, the coupling strength between the ele ctron and the dynamic defect, and the temperature. The results derived here are entirely different from those found in phonon-assisted reson ant tunneling, because phonons obey the Bose statistics but a two-leve l fluctuator behaves as an effective spin.