High-Q Nanomechanics via Destructive Interference of Elastic Waves

TL;DR

This paper investigates how destructive interference of elastic waves can significantly reduce support-induced dissipation in high-stress nanomechanical resonators, enhancing their quality factors.

Contribution

It introduces a model explaining dissipation mechanisms and predicts exponential suppression of clamping loss via wave interference in nanomechanical devices.

Findings

Measured Q-values show non-monotonic behavior explained by the model.

Destructive interference can exponentially suppress clamping loss.

Model applies to silicon nitride membranes and graphene drums.

Abstract

Mechanical dissipation poses an ubiquitous challenge to the performance of nanomechanical devices. Here we analyze the support-induced dissipation of high-stress nanomechanical resonators. We develop a model for this loss mechanism and test it on silicon nitride membranes with circular and square geometries. The measured Q-values of different harmonics present a non-monotonic behavior which is successfully explained. For azimuthal harmonics of the circular geometry we predict that destructive interference of the radiated waves leads to an exponential suppression of the clamping loss in the harmonic index. Our model can also be applied to graphene drums under high tension.