Effects of electrostatic force on piezoelectric materials under high electric field: Impact on GaN-based nanoscale structures

TL;DR

This paper investigates how electrostatic forces influence the electromechanical properties of piezoelectric materials, especially GaN-based nanoscale structures, revealing both quadratic and linear correction effects due to electric fields.

Contribution

It provides a thermodynamic analysis showing electrostatic forces cause both quadratic and linear corrections in piezoelectric materials, with specific focus on GaN-based nanoscale structures.

Findings

Corrections in piezoelectric coefficients exceed 0.3 pmV-1

Electrostrictive coefficient corrections surpass 2.6x10^-22 m^2V^-2

Both quadratic and linear effects are significant in nanoscale structures

Abstract

The determination of the electromechanical properties of materials for a parallel-plate capacitor structure is affected by the electrostatic force between their electrodes. The corrections induced by this electric-field-induced stress are usually assumed to be linked to the quadratic dependence of the strain on the electric field (electrostriction). Here we show by calculations based on thermodynamic grounds for this simple structure that the effect of the electrostatic force on piezoelectric materials can lead to both quadratic and linear corrections through the combination of the piezoelectric coupling and spontaneous polarization. The case of GaN-based capacitor nanoscale structures is presented taking into account the boundary conditions imposed as well as the effect of geometry. The results in this example point to corrections in the piezoelectric and electrostrictive coefficients higher than 0.3 pmV-1 and 2.6x10-22 m2V-2, respectively.