Diamond nanomechanical resonators protected by a phononic band gap

TL;DR

This paper demonstrates that diamond nanomechanical resonators protected by phononic band gaps achieve significantly enhanced Q-factors, surpassing 10^6 at high frequencies, promising for quantum applications.

Contribution

The study introduces a novel design of diamond cantilevers with phononic band gap protection, resulting in unprecedented mechanical Q-factors at high frequencies.

Findings

Q-factors exceed 10^6 at 100 MHz

Mechanical modes are protected by phononic band gaps

Q-factors limited by material loss at low temperatures

Abstract

We report the design, fabrication, and characterization of diamond cantilevers attached to a phononic square lattice. We show that the robust protection of mechanical modes by phononic band gaps leads to a three-orders-of-magnitude increase in mechanical Q-factors, with the Q-factors exceeding 10^6 at frequencies as high as 100 MHz. Temperature dependent studies indicate that the Q-factors obtained at a few K are still limited by the materials loss. The high-Q diamond nanomechanical resonators provide a promising hybrid quantum system for spin-mechanics studies.