Symmetry-determined antiferroelectricity in PbZrO3 , NaNbO3 , and

Like ferroelectric or ferroelastic phase transitions, antiferroelectric transitions can be predicted by symmetry. This property is illustrated by a theoretical analysis of the complex phase transitions, occurring in the perovskite compounds $\mathrm{PbZr}{\mathrm{O}}_{3}$, $\mathrm{NaNb}{\mathrm{O}}_{3}$, and $\mathrm{PbHf}{\mathrm{O}}_{3}$, which involve the coupling of several order parameters. The symmetry-breaking order parameters associated with the transitions in the three compounds are determined. The antiferroelectric transitions are shown to verify specific symmetry criteria, which consist of the emergence at the local scale of polar site symmetries coinciding with symmorphic subgroups of the antiferroelectric space group. The theoretical temperature--electric-field phase diagram of $\mathrm{PbZr}{\mathrm{O}}_{3}$ involving ferrielectric and ferroelectric phases is worked out.