THEORETICAL-EXAMINATION OF STRESS-FIELDS IN PB(ZR0.5TI0.5)O-3

In this paper, we develop a rigorous formulation of the local stress f ield. This approach can be used in conjunction with any first-principl es method to study stress fields in complex bonded systems. In particu lar we investigate the induced stress fields resulting from the homoge neous deformations of tetragonal PbTiO3 and rhombohedral PbZrO3. As an extension of these findings we also compute the induced stress fields resulting from homogeneous deformation of the (100) and (111) orderin gs of Pb(Zr0.5Ti0.5)O-3. The stress-field responses in these four mate rials are compared and their piezoelectric responses are discussed.