Multiscale Modeling of a Nanoelectromechanical Shuttle

TL;DR

This paper presents a multiscale theoretical model combining electronic structure and macroscopic dynamics to analyze nanoelectromechanical shuttling of a copper atom between electrodes, revealing dual stable modes and charge state effects.

Contribution

It introduces a novel multiscale approach integrating density functional theory with stochastic charge and Newtonian dynamics for nanoelectromechanical systems.

Findings

Shuttling involves only charge states Q=0 and Q=+e.

Two quasi-stable shuttling modes identified.

Random transitions occur between the modes.

Abstract

In this article, we report a theoretical analysis of a nanoelectromechanical shuttle based on a multiscale model that combines microscopic electronic structure data with macroscopic dynamics. The microscopic part utilizes a (static) density functional description to obtain the energy levels and orbitals of the shuttling particle together with the forces acting on the particle. The macroscopic part combines stochastic charge dynamics that incorporates the microscopically evaluated tunneling rates with a Newtonian dynamics. We have applied the multiscale model to describe the shuttling of a single copper atom between two gold-like jellium electrodes. We find that energy spectrum and particle surface interaction greatly influence shuttling dynamics; in the specific example that we studied the shuttling is found to involve only charge states Q=0 and Q=+e. The system is found to exhibit two quasi-stable shuttling modes, a fundamental one and an excited one with a larger amplitude of mechanical motion, with random transitions between them.