Polaronic memristor strongly coupled to electrodes

Attractive electron correlations due to an electron-vibron interaction (EVI) can overcome the direct Coulomb repulsion of polarons in strongly deformable molecular quantum dots (MQDs). If it realizes, a switching appears in the I-V characteristics of the degenerate nonadiabatic molecular bridges weakly coupled to electrodes providing a route to ultrafast `memristors' (memory-resistors) as the basis for future oscillators, amplifers, and other important circuit elements. Here, we extend our theory of polaronic memristors to adiabatic MQDs strongly coupled to the leads and show that the degeneracy of MQD (or other multilevel energy structure) along with the polaron-polaron attraction is a necessary ingredient of its switching behavior in the strong-coupling regime as well.