Fig. 1. An artificial superlattice assembled from perovskite nanosheets (A=Ca₂Nb₃O₁₀, B=LaNb₂O₇). The success of growth of such well-controlled superlattices with a good interface quality enabled us to explore new properties of perovskite superlattices. By artificial structuring, the group found that the (LaNb₂O₇/Ca₂Nb₃O₁₀) superlattice possesses a new form of interface coupling, which gives rise to ferroelectricity even at several nanometer thicknesses.