Cadmium-based ferroelectrics with the Ruddlesden–Popper and double perovskite structures: a theoretical study

The effect of substituting Ca by Cd in several Ca3B2O7 Ruddlesden–Popper (RP) and double perovskite (DP) CaCdB2O6 systems, where B is Mn or Ti, is here deeply investigated through ab initio calculations. We show that these cation substitutions have a high impact on the ferroelectric properties in such perovskite-based ferroelectrics. Our results reveal the relations between octahedra rotations with the atomic displacements responsible for inducing large electrical polarization in hybrid improper ferroelectrics. We show that these chemical substitutions tailor ferroelectric properties and can be used to engineer RP and DP systems, increasing their applicability range as ferroelectric or piezoelectric materials.