Image charge effects in the nonequilibrium Anderson-Holstein model

Abstract

Image charge effects in nanoscale junctions with strong electron-phonon coupling open the way to unexplored physical scenarios. We propose a simple and still accurate many-body approach to deal with the simultaneous occurrence of the Franck-Condon blockade and the screening-induced enhancement of the polaron mobility. A transparent analytic expression for the polaron decay rate is derived and the dependence on the strength and range of the screening is highlighted. This allows us to interpret and explain several transient and steady-state features of the electrical current. Remarkably, we find that the competition between the charge blocking due to the electron-phonon interaction and the charge deblocking due to the image charges gives rise to a novel mechanism of negative differential conductance. An experimental setup to observe this phenomenon is discussed.

Transient dynamics and waiting time distribution of molecular junctions in the polaronic regime

“…In a subsequent work [29] it was demonstrated that this apparent bistability actually corresponds to a long transient dynamics leading to blockingdeblocking events associated with the polaron dynamics. More recent work [30] has confirmed the analysis and also explored the effect of including the dot-leads Coulomb repulsion. The approach to the steady state has also been analyzed for the Anderson-Holstein model including a continuous distribution of phonon modes [31].…”

“…[28] it was shown that for certain parameter ranges the model exhibits an apparent bistable behavior. Further analysis [29,30] Fig. 2 (lower panel). full case.…”

Dressed tunneling approximation for electronic transport through molecular transistors

“…[42,60]. On the other hand, although the method has been derived for the more simple single model, the same ideas could be, in principle, extended to models including several dot levels coupled to multiple phonon modes like the one discussed in Ref.…”

Transient dynamics in the Anderson–Holstein model with interfacial screening

“…In the following we consider the continuum versionĤ c of the above model since it allows for a nonperturbative treatment of the e-e interaction via the bosonization technique 22 . To this end we first assume half-filled wide band leads with linear dispersion ǫ k = v F k (with v F = 2t w a the Fermi velocity and a the lattice spacing) and constant tunneling amplitude Γ = 2πT 2 l k δ(ω − ǫ k ) = 2T 2 l /t w , and then we unfold the left and right leads 21,23 . In this way the first term of Eq.…”