A numerical investigation of a piezoelectric surface acoustic wave interaction with a one-dimensional channel

TL;DR

This study uses finite element modeling to analyze how surface acoustic waves interact with a heterostructure featuring metallic gates and a 2DEG, revealing effects on wave attenuation and electron capture relevant for quantum device design.

Contribution

It presents a comprehensive 3D finite element approach to simulate SAW interactions with complex heterostructures, including electrical and mechanical effects and screening by 2DEG.

Findings

SAW amplitude attenuates due to gates

Electric potential modulation enables electron capture and release

No significant turbulence observed in SAW motion

Abstract

We investigate the propagation of a piezoelectric surface acoustic wave (SAW) across a GaAs/Al$_X$Ga$_{1-X}$As heterostructure surface, on which there is fixed a metallic split-gate. Our method is based on a finite element formulation of the underlying equations of motion, and is performed in three-dimensions fully incorporating the geometry and material composition of the substrate and gates. We demonstrate attenuation of the SAW amplitude as a result of the presence of both mechanical and electrical gates on the surface. We show that the incorporation of a simple model for the screening by the two-dimensional electron gas (2DEG), results in a total electric potential modulation that suggests a mechanism for the capture and release of electrons by the SAW. Our simulations suggest the absence of any significant turbulence in the SAW motion which could hamper the operation of SAW based quantum devices of a more complex geometry.