Research Update: Interface-engineered oxygen octahedral tilts in perovskite oxide heterostructures

Interface engineering of structural distortions is a key for exploring the functional properties of oxide heterostructures and superlattices. In this paper, we report on our comprehensive investigations of oxygen octahedral distortions at the heterointerface between perovskite oxides SrRuO₃ and BaTiO₃ on GdScO₃ substrates and of the influences of the interfacially engineered distortions on the magneto-transport properties of the SrRuO₃ layer. Our state-of-the-art annular bright-field imaging in aberration-corrected scanning transmission electron microscopy revealed that the RuO₆ octahedral distortions in the SrRuO₃ layer have strong dependence on the stacking order of the SrRuO₃ and BaTiO₃ layers on the substrate. This can be attributed to the difference in the interfacial octahedral connections. We also found that the stacking order of the oxide layers has a strong impact on the magneto-transport properties, allowing for control of the magnetic anisotropy of the SrRuO₃ layer through interface engineering. Our results demonstrate the significance of the interface engineering of the octahedral distortions on the structural and physical properties of perovskite oxides.