Finite-temperature properties of Pb(Zr1-xTix)O-3 alloys from first principles

A first-principles-derived approach is developed to study finite-temperatur e properties of Pb(Zr1-xTix)O-3 (PZT) solid solutions near the morphotropic phase boundary (MPB). Structural and piezoelectric predictions are in exce llent agreement with experimental data and direct first-principles results. A low-temperature monoclinic phase is confirmed to exist, and is demonstra ted to act as a bridge between the well-known tetragonal and rhombohedral p hases delimiting the MPB. A successful explanation for the large piezoelect ricity found in PZT ceramics is also provided.