Optimizing Phononic Crystal Waveguides for Acoustically Induced Spin Transport

TL;DR

This paper explores the design of phononic crystal waveguides with elliptical inclusions to enhance control over surface acoustic waves for quantum spin transport applications.

Contribution

It introduces a novel phononic crystal waveguide design using elliptical cylinders to create slow regions and reduce losses, advancing acoustic control for quantum information processing.

Findings

Designed a phononic crystal waveguide with elliptical inclusions

Achieved slow acoustic wave regions to improve control

Reduced coupling and radiative losses to bulk modes

Abstract

Through the use of strain and induced piezoelectric fields, surface acoustic waves have been shown to control quantum information processes, such as single photon emission and the coherent transport of electron spins. Regarding the latter, systems using plane surface waves have provided suitable demonstration systems, but to build complexity, more control over the acoustic wave may be required. One method for acoustic control is the use of phononic crystals consisting of periodic arrays of nanofabricated holes on the surface of a device. These inclusions form a metamaterial-like layer with properties different from the normal material to dictate the physics of wave motion. Exploiting these surface properties can lead to acoustic waveguides, which can be designed to control the path of the surface acoustic waves. The design parameters of a new type of phononic crystal waveguide is explored that uses 2-fold elliptical cylinder inclusions to create a slow region that also limits coupling and radiative loss to bulk acoustic modes. Such a waveguide would be the foundational piece in an acoustic circuit that could then mediate complex spin transport geometries.