  Atomic-scale precision epitaxy of perovskite oxide superlattices provides
unique opportunities for controlling the correlated electronic structures,
activating effective control knobs for intriguing functionalities including
electromagnetic, thermoelectric, and electrocatalytic behaviors. In this study,
we investigated the close interplay between the atomic and electronic
structures of correlated superlattices synthesized by atomic-scale precision
epitaxy. In particular, we employ superlattices composed of correlated magnetic
SrRuO3 (SRO) and quantum paraelectric SrTiO3 (STO) layers. In those
superlattices, RuO6 octahedral distortion is systematically controlled from 167
to 175 degrees depending on the thickness of the STO layers, also affecting the
TiO6 octahedral distortion within the STO layer. Customized octahedral
distortion within SRO/STO superlattices in turn modifies the electronic
structures of both the Ti and Ru compounds, observed by X-ray absorption
spectroscopy. Our results identify the close correlation between atomic lattice
and electronic structures enabled by the facile controllability of atomic-scale
epitaxy, which would be useful for designing future correlated oxide devices.
