A first-principles-derived approach was used to study the effects of planar defects on structural properties of a rocksalt-ordered Pb(Sc0.5Nb0.5)O3 alloy. These defects lead to unusual features, including a less symmetrical ground state with respect to the perfectly ordered material. It was also proposed that a simple and original mechanism, involving these defects, may be responsible for the existence and anomalous characteristics of the incommensurate phases observed in insulating perovskites.

Planar Defects and Incommensurate Phases in Highly Ordered Perovskite Solid Solutions. I.A.Kornev, L.Bellaiche: Physical Review Letters, 2002, 89[11], 115502 (4pp)