Low-Temperature Characteristics of an AlN/Diamond Surface Acoustic Wave Resonator

TL;DR

This study investigates how the quality factor of an AlN/diamond surface acoustic wave resonator varies from room temperature to 5 K, revealing phonon-phonon scattering as the main dissipation mechanism at low temperatures.

Contribution

It provides the first detailed analysis of the temperature dependence of the quality factor in AlN/diamond SAW devices down to 5 K, informing future device design.

Findings

Quality factor decreases with temperature, indicating phonon-phonon scattering.

Dissipation mechanism identified as Akheiser region phonon-phonon scattering.

Cooling below 5 K could further enhance device performance.

Abstract

Phonons confined in mechanical resonators can be coupled to a variety of quantum systems and are expected to be applied to hybrid quantum systems. Diamond surface acoustic wave (SAW) devices are capable of high efficiency in phonon interaction with color centers in diamond. The temperature dependence of the quality factor is crucial for inferring the governing mechanism of coupling efficiency between phonons and color centers in diamond. In this paper, we report on the temperature dependence of the quality factor of an AlN/diamond SAW device from room temperature to 5 K. The temperature dependence of the quality factor and resonant frequency suggests that the mechanism of SAW dissipation in the AlN/diamond SAW resonator at 5 GHz is the phonon-phonon scattering in the Akheiser region, and that further cooling can be expected to improve the quality factor. This result provides a crucial guideline for the future design of AlN/diamond SAW devices.