Nonlinear modal coupling in a high-stress doubly-clamped nanomechanical resonator

TL;DR

This study investigates the nonlinear coupling between vibrational modes in a high-stress silicon nitride nanomechanical beam at cryogenic temperatures, revealing mode interactions driven by tension-induced nonlinearities.

Contribution

It provides experimental evidence of intermodal nonlinear coupling in a high-stress nanomechanical resonator, highlighting the role of tension-induced nonlinearities in mode interactions.

Findings

Modes exhibit nonlinear behavior individually.

Modes are coupled via tension-induced nonlinearities.

Duffing nonlinearity observed in the resonator.

Abstract

We present results from a study of the nonlinear intermodal coupling between different flexural vibrational modes of a single high-stress, doubly-clamped silicon nitride nanomechanical beam. The measurements were carried out at 100 mK and the beam was actuated using the magnetomotive technique. We observed the nonlinear behavior of the modes individually and also measured the coupling between them by driving the beam at multiple frequencies. We demonstrate that the different modes of the resonator are coupled to each other by the displacement induced tension in the beam, which also leads to the well known Duffing nonlinearity in doubly-clamped beams.