Local octahedral correlations at a single snapshot in time inferred from the experimentally derived QEDS in FAPbBr3. Each octahedron is represented by a sphere in which the colour represents the respective tilt angle along the c crystallographic direction, with blue corresponding to positive; red, to negative; and white, to a random close-to-zero tilt angle. Local octahedral tilts in MAPbBr3 form planar/pancake-like correlations, with the octahedra correlated out-of-phase in the c direction, whereas in FAPbBr3, correlations are more isotropic, forming spherical nanodomains of octahedra that are correlated in-phase along the c direction. Nanodomain sizes are defined by correlation lengths ⊥ and ∥ , as depicted in e.
