Effect of a Single Dislocation in a Heterostructure Layer on the Local Polarization of a Ferroelectric Layer

We study, on an atomic scale, the influence of a single dislocation in a SrTiO₃ sublayer on the local ferroelectric polarization of the neighboring ferroelectric PbZr0.2Ti0.8O₃ (PZT) sublayer in an epitaxial SrTiO₃/PbZr0.2Ti0.8O₃/SrTiO₃ three-layer heterostructure. The strain field of the dislocation in the SrTiO₃ layer propagates across the interface into the PZT layer and leads to a strong variation of the c-lattice parameter of the PZT layer. Accompanying a strong reduction of the c-lattice parameter, the off-center displacements of the Zr/Ti atoms away from the center of the oxygen octahedra are also strongly decreased, resulting in a decrease of the local spontaneous polarization by up to 48%.