In situ observation of the interfacial lattice reconstruction in SrRuO3/SrTiO3 heterostructures driven by the SrTiO3 phase transition

The change in physical properties of epitaxial $\mathrm{SrRu}{\mathrm{O}}₃/\mathrm{SrTi}{\mathrm{O}}₃$ (SRO/STO) heterostructures occurring at the STO phase-transition temperature of 105 K has attracted enormous research interest. In this work, we have investigated the interfacial lattice structures in the SRO/STO heterostructure below and above 105 K. Based on the high-resolution structural analysis and ultrafast x-ray-diffraction experiments, we have revealed an interfacial lattice reconstruction of the SRO layer both in the real space and reciprocal space. Such an interfacial lattice reconstruction can be attributed to the cubic-to-tetragonal transition that occurs in structural transitions of the STO substrate.