Abstract
Structural and elastic properties of Pb(Zr0.50Ti0.50)O3 are determined in the tetragonal ferroelectric phase using first-principles density functional theory in the local-density approximation. Three ordered arrangements of PZT are considered and compared with a homogeneously disordered model of PZT treated in the virtual-crystal approximation. The ground states of some of these model PZT structures are found to be monoclinic; others, including the energetically most stable structure, are tetragonal.