Application of a new virtual crystal approach for the study of disordered perovskites

The "virtual crystal" (VC) approach is a tractable way of studying configur ationally disordered systems; the potentials which represent atoms of two o r more elements are averaged into a composite atomic potential. This approa ch has the advantage that a single configuration with a smaller unit cell r epresents the disordered system. However, due to the different local enviro nment of the virtual atom, some properties may not be reproduced. In this w ork, we develop a new virtual crystal approach and apply it to the study of the stress-induced phase transition in Pb(Zr1/2Ti1/2)O-3 We compare four a veraging algorithms for the construction of the virtual atom pseudo-potenti als and we assess the accuracy of each by comparing with a superlattice pre diction of the equations of state. (C) 1999 Elsevier Science Ltd. All right s reserved.