Polaronic effects induced by non-equilibrium vibrons in a single-molecule transistor

TL;DR

This paper investigates how non-equilibrium vibrons in a vibrating quantum dot affect the current-voltage characteristics of a single-electron transistor, revealing suppression of conductance and step-like features in the I-V curves.

Contribution

It introduces a model for vibrons in a non-equilibrium state and predicts novel effects on conductance and polaronic blockade in single-molecule transistors.

Findings

Strong suppression of conductance at large oscillation amplitudes

Lifting of polaronic blockade by bias voltage

Distinct step features in I-V curves differing from equilibrium predictions

Abstract

Current-voltage characteristics of a single-electron transistor with a vibrating quantum dot were calculated assuming vibrons to be in a coherent (non-equilibrium) state. For a large amplitude of quantum dot oscillations we predict strong suppression of conductance and the lifting of polaronic blockade by bias voltage in the form of steps in $I-V$ curves. The height of the steps differs from the prediction of the Franck-Condon theory (valid for equilibrated vibrons) and the current saturates at lower voltages then for the case, when vibrons are in equilibrium state.