Polarization enhancement in two- and three-component ferroelectric superlattices

Composition-dependent structural and polar properties of epitaxial short-period CaTiO3/-SrTiO3/BaTiO3 superlattices grown on a SrTiO3 substrate are investigated with first-principles density-functional theory computational techniques. Polarization enhancement with respect to bulk tetragonal BaTiO3 is found for two- and three-component superlattices with a BaTiO3 concentration of more than 30%. Individual BaTiO3 layer thickness is identified as an important factor governing the polarization improvement. In addition, the degree of inversion-symmetry breaking in three-component superlattices can be controlled by varying the thicknesses of the component layers. The flexibility allowed within this large family of structures makes them highly suitable for various applications in modern nanoelectromechanical devices. (c) 2005 American Institute of Physics.