Damping of Nanomechanical Resonators

TL;DR

This paper investigates the damping mechanisms of high-stress nanomechanical silicon nitride resonators, combining experimental measurements with classical elastic theory to understand mode-dependent damping and the influence of tensile stress.

Contribution

It introduces a model that predicts mode-dependent damping in nanomechanical resonators based on local strain and tensile stress effects, validated by experimental data.

Findings

Resonance frequencies match classical elastic theory predictions.

Damping behavior can be modeled with a single frequency-independent parameter.

Tensile stress significantly influences damping mechanisms.

Abstract

We study the transverse oscillatory modes of nanomechanical silicon nitride strings under high tensile stress as a function of geometry and mode index m <= 9. Reproducing all observed resonance frequencies with classical elastic theory we extract the relevant elastic constants. Based on the oscillatory local strain we successfully predict the observed mode-dependent damping with a single frequency independent fit parameter. Our model clarifies the role of tensile stress on damping and hints at the underlying microscopic mechanisms.