LAUSR

We investigate in-plane ferroelectricity in an epitaxial ferroelectric |dielectric PbTiO 3 | SrTiO 3 (PTO |STO) superlattice under tensile strain. Using a combination of x-ray diffraction and piezoresponse force microscopy, we identify a strain-induced periodic in-plane nanoscale domain architecture with polarization along the base diagonals of the PTO unit cell. We scrutinize its switching behavior using local in-plane trailing fields from the scanning-probe tip. For an electric field pointing in the polarization direction of a specific domain state, we create stable single-domain areas of in-plane polarization at the scale of tens of micrometers. Our findings on controlling robust in-plane ferroelectricity in ultrathin ferroelectric layers can help one to develop device concepts unaffected by the detrimental effects of the depolarizing field.