Screening-induced negative differential conductance in the Franck-Condon blockade regime

TL;DR

This paper introduces a many-body approach to analyze how screening effects influence electron transport in nanoscale junctions with strong electron-phonon interactions, revealing a new negative differential conductance mechanism.

Contribution

The work provides an analytic expression for current considering both Franck-Condon blockade and screening effects, explaining transient and steady-state behaviors.

Findings

Identification of a novel negative differential conductance mechanism

Derivation of a transparent analytic current expression

Discussion of experimental setups to observe the phenomenon

Abstract

Screening effects in nanoscale junctions with strong electron-phonon coupling open new physical scenarios. We propose an accurate many-body approach to deal with the simultaneous occurrence of the Franck-Condon blockade and the screening-induced enhancement of the polaron mobility. We derive a transparent analytic expression for the electrical current: transient and steady-state features are directly interpreted and explained. Moreover, the interplay between phononic and electronic excitations gives rise to a novel mechanism of negative differential conductance. Experimental setup to observe this phenomenon are discussed.