Ferroelectricity in artificial bicolor oxide superlattices

Bicolor oxide superlattices with one- and two-unit-cell layer thickness (see figure) are explored by advanced synthesis, characterization, and first-principles calculation. Experimentally, enhanced ferroelectric polarization is observed for the superlattice of which chemical composition lies beyond the solubility limit. Theoretical analyses reveal that ferroelectric corrugation occurs in a paraelectric layer in the superlattice and plays important roles in both stabilization and enhancement of ferroelectricity.