Comparison of [111] and [001] B-site stacking order in PZN-type relaxor ferroelectrics

Abstract

It has recently been shown that single-crystal solid solution ferroelectric crystals can have dramatically improved electromechanical properties compared to conventional transducer materials. This discovery has stimulated research aimed at understanding the atomic structures of these materials and identifying parameters controlling the growth of large crystals. We have investigated PZN-type relaxors with the stoichiometry Pb(Zn 1/3 2+Nb 2/3 5+)O 3, using the first-principles ab initio projector mixed-basis method. We have analyzed well-converged structures and energetics of both P4/mmm space group [001] stacking vs. P3m1 [111] stacking. The atomic positions in each compositional structure are relaxed using calculated forces and a velocity-based MD relaxation method. The calculations reveal a preference for P3m1 [111] stackings.