Fig. 1
From: Inversion symmetry and bulk Rashba effect in methylammonium lead iodide perovskite single crystals
SHG rotational anisotropy experiments. Polar plots of the SHG-RA data (blue dots) from the (100) surface of MAPbI3, where each panel shows results for a different set of incident and outgoing polarizations. The radial direction represents the normalized magnitude of the SHG intensity and the azimuthal angle ϕ the orientation of the light scattering plane relative to the tetragonal a-axis. The expected electric-dipole SHG radiation patterns from the bulk of a I4cm crystal (black) and best fits of the data to electric-dipole SHG radiation patterns from the surface of a I4/mcm crystal (red) are superposed on top of the data. In the latter case, SHG is forbidden by symmetry in Sin−Sout geometry
