Theoretical Investigation of Spontaneous Polarization and Dielectric Constant of BaTiO3/SrTiO3 Superlattices

The spontaneous polarization and dielectric constant of BaTiO3 (BT)/SrTiO3 (ST) superlattices epitaxially grown on ST substrate are theoretically investigated using a microscopic quantum mechanical model based on the orbital approximation in correlation with the dipole-dipole interaction. Both the first-, second-, and third-order electronic polarizabilities were considered in this calculation in order to obtain accurate results for both the spontaneous polarization and relative dielectric constant of BT/ST superlattices. The calculations show that the spontaneous polarization of BT/ST superlattices increases with their richness in BT while the relative dielectric constant increases with their richness in ST.