Spontaneous polarization and piezoelectric constants of III-V nitrides

TL;DR

This paper investigates the spontaneous polarization and piezoelectric properties of III-V nitrides using ab initio methods, revealing significantly larger piezoelectric constants and unique polarization characteristics compared to conventional III-V compounds.

Contribution

It provides the first ab initio calculations of polarization and piezoelectric constants for AlN, GaN, and InN, highlighting their exceptional piezoelectric response.

Findings

Piezoelectric constants are up to 10 times larger than in conventional III-Vs.

The sign of the piezoelectric constants is positive, similar to II-VI compounds.

Spontaneous polarization is very large and differs from conventional III-Vs.

Abstract

The spontaneous polarization, dynamical Born charges, and piezoelectric constants of the III-V nitrides AlN, GaN, and InN are studied ab initio using the Berry phase approach to polarization in solids. The piezoelectric constants are found to be up 10 times larger than in conventional III-V's and II-VI's, and comparable to those of ZnO. Further properties at variance with those of conventional III-V compounds are the sign of the piezoelectric constants (positive as in II-VI's) and the very large spontaneous polarization.