Propagation Control of Octahedral tilt in Atomically Designed Oxide Heterostructures

Designing of oxide heterostructure is a promising pathway for studying the emergent functional properties of transition metal oxides, including metal-insulator transition, spin-phonon coupling, and topologically nontrivial phases. In particular, customization of octahedral bonding geometry plays an essential role in tailoring the functionalities owing to its strong correlation to charge, spin, and orbital degrees of freedom.
Here, we propose a strategy to selectively modulate the octahedral bonding geometries via atomic-scale heterostructuring. We used atomically designed SrRuO₃/SrTiO₃ superlattices to demonstrate the octahedral tilt propagation engineering.^[1-3] The propagation of RuO₆ octahedral tilt within SrRuO₃ layers was systematically controlled by changing the thickness of adjacent SrTiO₃ layers. The approach provides accessible controllability of ferromagnetic properties of SrRuO₃ layers with the same thickness and stoichiometry. The strong interplay between the lattice and orbital degrees of freedom implies a possible mechanism of the atomic structure-dependent ferromagnetism in SrRuO₃.

[1] S. G. Jeong et al., Phys. Rev. Lett. 124, 026401 (2020).
[2] S. G. Jeong et al., Nanoscale. 12, 13926 (2020).
[3] S. G. Jeong et al., Adv. Sci. 7, 2001643 (2020).