A thermodynamic model and estimation of the experimental value of spontaneous polarization in a wurtzite GaN

Abstract

Determining the spontaneous polarization is a fundamental problem in the III-nitride field. However the experimental value of the spontaneous polarization has not yet been reported. In this study, a thermodynamic model is proposed to investigate the spontaneous polarization of GaN from the GaN high-pressure phase transition. Total macroscopic polarization is directly expressed as coefficients in expansion, and these coefficients are found to be conducted in experiments. The experimental value of the spontaneous polarization of GaN is estimated to be around −0.022 C/m2.