Oxygen-induced surface reconstruction of SrRuO₃ and its effect on the BaTiO₃ interface

Atomically engineered oxide multilayers and superlattices display unique properties responsive to the electronic and atomic structures of the interfaces. We have followed the growth of ferroelectric BaTiO₃ on SrRuO ₃ electrode with in situ atomic scale analysis of the surface structure at each stage. An oxygen-induced surface reconstruction of SrRuO ₃ leads to formation of SrO rows spaced at twice the bulk periodicity. This reconstruction modifies the structure of the first BaTiO ₃ layers grown subsequently, including intermixing observed with cross-section spectroscopy. These observations reveal that this common oxide interface is much more interesting than previously reported and provide a paradigm for oxygen engineering of oxide structure at an interface.