High performance lead free ferroelectric ATiO3/SnTiO3 superlattices.

Perovskite SnTiO3 (SNO) was predicted to be ferroelectric with a large spontaneous polarization. However, the perovskite phase SNO was found to be metastable in experiments. Here, we show that SNO perovskite phase can be stabilized by the interfacial geometry in ATiO3/SNO superlattices (A = Ca, Sr, Ba) of short periodicity using first principles calculations. We found that CaTiO3/SNO superlattice has the largest polarization. In all the superlattices investigated, a phase transition from tetragonal to monoclinic structure was found with increasing in-plane lattice constants. Accompanying this phase transition, polarization directions rotate from [001] to [110], which is promising for achieving large piezoelectric responses. [ABSTRACT FROM AUTHOR]