Stress-Induced Phase Transition in Pb(Zr1/2Ti1/2)O3 : Tetragonal to rhombohedral transition

Stress-Induced Phase Transition in Pb(Zr1/2Ti1/2)O3


Abstract. We investigate, within local density functional theory, the structural phase stability of the piezoelectric material Pb(Zr1/2Ti1/2)O3 (PZT) under finite applied uniaxial stress. Previous theoretical analyses of piezoelectric properties have examined the behavior of the system near the ground-state structure. However, because some piezoelectrics can accept large (> 1%) strains reversibly [J. Appl. Phys. 82, 1804 (1997)], these crystals are clearly operating beyond their lowest-order behavior, and insight can be gained from studying piezoelectricity at finite strain. We have studied the structural properties of the (111)-PZT crystal over a range of positive and negative uniaxial strains. For each strain state, we identity two metastable structures: a tetragonal phase and a low-symmetry rhombohedral-like phase. For each phase, we determine the evolution of the magnitude and direction of polarization in the crystal as a function of applied stress. We also analyze the energetic and structural profile of the stress-induced tetragonal-to-rhombohedral phase transition. In particular, we compute the transition stress, and we identify the accompanying atomic motions in terms of larger structural motifs such as cation motion within oxygen cages and oxygen-cage tilting.


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