Optical Magnetoelectric Effect in a Polar Ferromagnetic Two-Dimensional Organic–Inorganic Hybrid Perovskite

Magnetoelectric effect is a coupling phenomenon between magnetism and dielectric properties that occurs in noncentrosymmetric magnetic materials. This effect can be extended to the response to electromagnetic waves, i.e., light, in materials and is referred to as the optical magnetoelectric (OME) effect. The OME effect can give rise to fascinating optical properties, such as propagation-direction-dependent light absorption, known as nonreciprocal directional dichroism. In this study, we prepared single crystals of a polar and ferromagnetic two-dimensional organic–inorganic hybrid perovskite (2D-OIHP) copper chloride, (ClBA) 2 CuCl 4 (where ClBA + = 4-chlorobenzylammonium ion), with sufficient size for optical measurements, and successfully detected the OME effect by measuring the difference in light absorption between opposite propagation directions. These results suggest that 2D-OIHPs are a promising class of materials for developing emergent functionalities unique to noncentrosymmetric systems.