Structural origins of the properties of rare earth nickelate superlattices

摘要

NiO6 octahedral tilts in the LaNiO3/SrTiO3 superlattices are quantified usingposition averaged convergent beam electron diffraction in scanning transmissionelectron microscopy. It is shown that maintaining oxygen octahedra connectivityacross the interface controls the octahedral tilts in the LaNiO3 layers, theirlattice parameters and their transport properties. Unlike films and layers thatare connected on one side to the substrate, subsequent LaNiO3 layers in thesuperlattice exhibit a relaxation of octahedral tilts towards bulk values. Thisrelaxation is facilitated by correlated tilts in SrTiO3 layers and iscorrelated with the conductivity enhancement of the LaNiO3 layers in thesuperlattices relative to individual films.