Toward Enhanced Inertial Sensing via Dynamically Soft Topological States in Piezoelectric Microacoustic Metamaterials

TL;DR

This paper introduces a piezoelectric microacoustic device leveraging topological interface states to significantly enhance inertial sensing, achieving record-high particle velocities surpassing previous gyroscope capabilities.

Contribution

It demonstrates, both theoretically and experimentally, that topological interface states in metamaterials can greatly increase modal compliance and particle velocity in piezoelectric gyroscopes.

Findings

Achieved particle velocities over 51 m/s, the highest for piezoelectric gyroscopes.

Topological interface states provide higher compliance than traditional Lamb or Rayleigh modes.

Experimental validation confirms theoretical predictions of enhanced performance.

Abstract

In recent decades, microelectromechanical systems (MEMS)-based gyroscopes have been employed to meet positioning and navigation demands of a plethora of commercially available devices. Most of such gyroscopes rely on electrostatic actuators with nanometer-scale air gaps$\unicode{x2013}$an architecture that enables large particle velocities in a proof mass and, consequently, high Coriolis-force sensitivity to angular velocity$\unicode{x2013}$but is inherently susceptible to damage under shock and vibration. This vulnerability is typically mitigated by purposely reducing gyroscopic sensitivity, thereby compromising readout accuracy. Microacoustic gyroscopes, by contrast, offer greater resilience to shock and vibration but currently exhibit significantly lower sensitivities. This limitation stems from the low dynamic compliance of the modes they employ$\unicode{x2013}$typically Lamb or Rayleigh modes$\unicode{x2013}$which restricts their maximum achievable particle velocity. This work presents a piezoelectric microacoustic device that overcomes this fundamental constraint by harnessing a topological interface state at the boundary between two microscale metamaterial structures. We theoretically and experimentally show that this state exhibits much higher modal compliance than Lamb or Rayleigh modes. This enables record-high particle velocities (>51 m/s) never reached, due to material limits, by any previously demonstrated piezoelectric gyroscope.