Strain induced ferroelectricity in the SrZrO3 / SrTiO3 superlattice: First principles study

The lattice distortion strain induced ferroelectricity in SrZrO3/ SrTiO3 superlattice is studied using first principles density functional theory. Within the tetragonal symmetry P4mm, the lattice distortion from the lattice mismatch in the superlattice structure is determined through energy minimization. This kind of lattice distortion leads to the formation of spontaneous polarization in the superlattice, although neither SrZrO3 nor SrTiO3 is ferroelectric. From analysis of the relative displacements of the cations and anions, we have found that the SrZrO3 cell may make a greater contribution to the polarization in the SrZrO3/ SrTiO3 superlattice than the SrTiO3 cell. An extremely large polarization of 42.7 μC/cm2 has been predicted.