Predicting polarization enhancement in multicomponent ferroelectric superlattices

Ab initio calculations are utilized as an input to develop a simple model of polarization in epitaxial short-period $\mathrm{Ca}\mathrm{Ti}{\mathrm{O}}_3∕\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3∕\mathrm{Ba}\mathrm{Ti}{\mathrm{O}}_3$ superlattices grown on a $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$ substrate. The model is then combined with a genetic algorithm technique to optimize the arrangement of individual $\mathrm{Ca}\mathrm{Ti}{\mathrm{O}}_3$, $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$, and $\mathrm{Ba}\mathrm{Ti}{\mathrm{O}}_3$ layers in a superlattice, predicting structures with the highest possible polarization and a low in-plane lattice constant mismatch with the substrate. This modeling procedure can be applied to a wide range of layered perovskite-oxide nanostructures providing guidance for experimental development of nanoelectromechanical devices with substantially improved polar properties.