Bistability signatures in nonequilibrium charge transport through molecular quantum dots

TL;DR

This paper explores how the steady state current in molecular quantum dots can exhibit bistability depending on initial conditions, influenced by bias voltage and vibrational interactions, with implications for nanoelectromechanical systems.

Contribution

It demonstrates the presence of bistability signatures in nonequilibrium charge transport through molecular quantum dots using exact numerical methods.

Findings

Steady state current depends on initial system preparation.

Bistability signatures are influenced by bias voltage and vibrational coupling.

Potential connection to stochastic switching in nanoelectromechanical devices.

Abstract

We investigate the transient nonequilibrium dynamics of a molecular junction biased by a finite voltage and strongly coupled to internal vibrational degrees of freedom. Using two different, numerical exact techniques, diagrammatic Monte Carlo and the multilayer multiconfiguration time-dependent Hartree method, we show that the steady state current through the junction may depend sensitively on the initial preparation of the system, thus revealing signatures of bistability. The influence of the bias voltage and the transient dynamics on the phenomenon of bistability is analyzed. Furthermore, a possible relation to the phenomenon of stochastic switching in nanoelectromecanical devices is discussed.