Cation ordering induced polarization enhancement for $PbTi{O}_3$-$SrTi{O}_3$ ferroelectric-dielectric superlattices

Abstract

In this paper, an efficient computational material design approach (cluster expansion) is employed for the ferroelectric $PbTi{O}_3$/$SrTi{O}_3$ system. Via exploring a conguration space including over $3\times 10^6$ candidates, two special cation ordered configurations: either perfect or mixed 1/1 (101) superlattice, are identified with the mostly enhanced ferroelectric polarization by up to about 100% in comparison with the (001) superlattice. Analyzing these two special configurations reveals the exotic couplings between the antiferrodistortive distortion (AFD) and ferroelectric polarization (FE) modes, e.g., tilting along x or y axis and polarization in z direction, as the origin for the best polarization property in this system. The identified cation ordering motifs and the exotic AFD-FE couplings could provide fresh ideas to design multifunctional perovskite heterostructures.

5 pages, 4 figures and 1 table