Misfit strain-misfit strain phase diagram of (110)-oriented ferroelectric PbTiO₃ films: a phase-field study

Ferroelectric thin films with high index orientations are found to possess unique structures and properties. In this work, we constructed the misfit strain-misfit strain phase diagram of (110)-oriented PbTiO3 (PTO) thin films by phase-field simulations. The evolutions of ferroelectric phase structures, domain morphologies, volume fractions, and polarization components with the anisotropic strains were analyzed in detail. Large anisotropic strains exist between the orthorhombic scandate substrates and (110)-oriented PTO films, which makes it possible to engineer the structures and properties by anisotropic strain. These results deepen the understanding of ferroelectric domain structures of (110)-oriented PTO films under the anisotropic strain and provide theoretical support for the anisotropic strain engineering of high-index thin films experimentally.