Strain Effects on Structural and Magnetic Properties of SrIrO₃/SrTiO₃ Superlattice

Combining first principles technique with experimental studies, the effects of strain on the structural and magnetic properties of ¹(SrIrO3)-¹(SrTiO3) (SIO-STO) are investigated. The SIO-STO superlattice has a stable a^-b^-c^- rotational pattern, from density functional theory calculations, and it is consistent with X-ray diffraction measurements. The structural responses, including octahedra rotation and tilting, as a function of epitaxial strain are established. The Ir atoms form a stable in-plane anti-ferromagnetic configuration with moderate spin canting. In this study, we find that tensile strain significantly increases the in-plane octahedral rotation and the exchange anisotropy, suggesting a prominent magnetoelastic coupling in SIO-STO. In addition, the strain-induced variation of orbital moment is significantly larger than that of the spin moments. The interplay among structural distortions, spin canting and Dzyaloshinskii-Moriya interaction is analyzed to provide a fundamental understanding of such magnetoelastic behavior in SIO-STO superlattice.