  We perform first-principles density functional calculations to explore the
role of substrate proximity effects on the octahedral rotation patterns in
perovskite oxide superlattices. With cubic perovskite SrFeO$_3$ as our model
film and tetragonal SrTiO$_3$ as the substrate, we show that in most cases the
substrate octahedral rotation patterns propagate into the film across the
heterointerface. We also identify elastic boundary conditions for which the
enforced structural coherence induces atomic displacement patterns that are not
found in the bulk phase diagram of either individual constituent. We suggest
that such substrate coherency-induced octahedral texturing of thin film oxides
is a promising approach for tuning the electronic structure of functional oxide
thin films.
