Effects of antiphase boundaries on the structural properties of highly ordered perovskite solid solutions

Using first-principles-derived techniques, we investigated the effects of antiphase boundaries on the structural properties of rocksalt-ordered Pb(Sc0.5Nb0.5)O3 alloy. Unusual features are predicted to occur, including (1) a ferroelectric monoclinic MA phase for ground state, (2) the activation of off-center optical phonons, and (3) a large spread of the PbO bonds. All the features can be understood by simple arguments. (Author)