A dynamical model for Brownian molecular motors driven by inelastic electron tunneling

TL;DR

This paper introduces a dynamical model for artificial Brownian molecular motors driven by inelastic electron tunneling, validating it with experimental data and analyzing the influence of current-induced forces on their behavior.

Contribution

The paper develops a new dynamical model for electrically driven molecular motors, enabling better understanding and parameter extraction, with analysis of current-induced forces effects.

Findings

Model aligns with experimental data

CIFs nonconservative effects are minor in analyzed cases

Conservative CIFs can significantly influence dynamics

Abstract

In recent years, several artificial molecular motors driven and controlled by electric currents have been proposed. Similar to Brownian machines, these systems work by turning random inelastic tunneling events into a directional rotation of the molecule. Despite their importance as the ultimate component of future molecular machines, their modeling has not been sufficiently studied. Here, we develop a dynamical model to describe these systems. We illustrate the validity and usefulness of our model by applying it to a well-known molecular motor, showing that the obtained results are consistent with the available experimental data. Moreover, we demonstrate how to use our model to extract some difficult-to-access microscopic parameters. Finally, we include an analysis of the expected effects of current-induced forces (CIFs). Our analysis suggests that, although nonconservative contributions of the CIFs can be important in some scenarios, they do not seem important in the analyzed case. Despite this, the conservative contributions of CIFs could be strong enough to significantly alter the system's dynamics.