<i>Ab initio</i>study of the spontaneous polarization of pyroelectric BeO

Abstract

The spontaneous bulk polarization of wurtzite BeO is studied using ground-state first-principles theory. This quantity, which is not accessible when imposing periodic boundary conditions, is obtained with a novel approach based on the supercell method. The calculated macroscopic polarization is ${\mathit{P}}_{3}$=1.5\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}2}$ C/${\mathrm{m}}^{2}$, and mostly results from the internal crystallographic distortion. No experimental value of ${\mathit{P}}_{3}$ exists, but the calculated differences in polarization, between different geometries, compare well with available data.