Fig. 2

3D electron densities reconstructed by COBRA at 30 K. Three-dimensional electron densities for a CaTiO₃/NdGaO₃, b CaTiO₃/DyScO₃, c CaTIO₃/LSAT at 30 K reconstructed by coherent Bragg rods analysis (COBRA). Polarizations projections on ac and bc planes are displayed on corresponding faces. Oxygen octahedra tilts evolution, α, β, and γ, are magnified by 5 times and displayed by red, green, and blue pie charts along each edge of electron densities. One of the four equivalent CaTiO₃ domains on LSAT are plotted for convenience of comparison. Two-dimensional slices of d ac, e bc, and f ab planes for CaTiO₃/NdGaO₃ and the corresponding plots g, h, i, for CaTiO₃/LSAT are shown, respectively. The interconnected oxygen networks are sketched by black squares, which tends to clamp the in-plane tilts (α and β) in CaTiO₃ through interface. While, the γ tilt in CaTiO₃ is unaffected