Nanomechanical resonators based on adiabatic periodicity-breaking in a superlattice

TL;DR

This paper introduces a new method for confining mechanical modes in a superlattice by adiabatically altering its properties, demonstrated through experiments at 350 GHz, with tunable mode profiles and potential applications in nanophononics.

Contribution

It presents a novel adiabatic confinement technique in superlattices, validated by experiments and simulations, enabling tunable mechanical modes for nanophononic systems.

Findings

Confined acoustic mode observed at 350 GHz.

Excellent agreement between experiment and simulation.

Mode profile and quality factor can be tuned via adiabatic deformation.

Abstract

We propose a novel acoustic cavity design where we confine a mechanical mode by adiabatically changing the acoustic properties of a GaAs/AlAs superlattice. By means of high resolution Raman scattering measurements, we experimentally demonstrate the presence of a confined acoustic mode at a resonance frequency around 350 GHz. We observe an excellent agreement between the experimental data and numerical simulations based on a photoelastic model. We demonstrate that the spatial profile of the confined mode can be tuned by changing the magnitude of the adiabatic deformation, leading to strong variations of its mechanical quality factor and Raman scattering cross section. The reported alternative confinement method could lead to the development of a novel generation of nanophononic and optomechanical systems.