Surface dissipation in nanoelectromechanical systems: Unified description with the standard tunneling model and effects of metallic electrodes

TL;DR

This paper develops a theoretical framework to describe surface dissipation in nanoelectromechanical systems, accounting for effects of metallic electrodes and comparing predictions with experimental data.

Contribution

It extends the standard tunneling model to surface dissipation in nanoelectromechanical devices and analyzes the impact of metallic electrodes on friction mechanisms.

Findings

Qualitative agreement with experimental quality factors and frequency shifts

Scaling laws for dissipation with system dimensions and temperature

Identification of limitations in current models for quantitative predictions

Abstract

By modifying and extending recent ideas [C. Seoanez et al., Europhys. Lett. 78, 60002 (2007)], a theoretical framework to describe dissipation processes in the surfaces of vibrating micro- and nanoelectromechanical devices, thought to be the main source of friction at low temperatures, is presented. Quality factors as well as frequency shifts of flexural and torsional modes in doubly clamped beams and cantilevers are given, showing the scaling with dimensions, temperature, and other relevant parameters of these systems. Full agreement with experimental observations is not obtained, leading to a discussion of limitations and possible modifications of the scheme to reach a quantitative fitting to experiments. For nanoelectromechanical systems covered with metallic electrodes, the friction due to electrostatic interaction between the flowing electrons and static charges in the device and substrate is also studied.