Importance of second-order piezoelectric effects in zincblende semiconductors

TL;DR

This paper demonstrates that second-order piezoelectric effects significantly influence the electric field in zincblende semiconductors like GaAs and InAs, especially under large strains, challenging the traditional linear approximation.

Contribution

It introduces the calculation of second-order piezoelectric tensors using density functional theory and highlights their importance in realistic quantum well scenarios.

Findings

Second-order effects can dominate the piezoelectric field at large strains.

Linear and quadratic coefficients have opposite effects on the field.

First- and second-order contributions are of comparable magnitude.

Abstract

We show that the piezoelectric effect that describes the emergence of an electric field in response to a crystal deformation in III-V semiconductors such as GaAs and InAs has strong contributions from second-order effects that have been neglected so far. We calculate the second-order piezoelectric tensors using density functional theory and obtain the piezoelectric field for [111]-oriented In$_x$Ga$_{1-x}$As quantum wells of realistic dimensions and concentration $x$. We find that the linear and the quadratic piezoelectric coefficients have the opposite effect on the field, and for large strains the quadratic terms even dominate. Thus, the piezoelectric field turns out to be a rare example of a physical quantity for which the first- and second-order contributions are of comparable magnitude.