Separation of Isotropic and Anisotropic Tensor for MAPbI3 Perovskite Crystal Using Group Theory and Simplified Bond Hyperpolarizability Model.

Abstract

Nonlinear phenomena occur when the electric field from a coherent and high-intensity light source interacts with the atoms in the material so that it oscillates anharmonically along the bond. Optical nonlinearities can be used as a method for analyzing the structure of optoelectronic materials such as perovskite. MAPbI3 is an optoelectronic material that has advantage in conservation efficiency, at room temperature MAPbI3 has an orthorhombic structure with C2v group points on the surface and D4h in the bulk perovskite section. This research separates the isotropic and anisotropic susceptibility tensors in the case of the second harmonic generation and the third harmonic generation and analyzes their contribution to total polarization. there are 6 isotropic non-zero tensor components and 13 non-zero anisotropic components in the C2V rank-3 structure and zero isotropic and anisotropic components in the D4h rank-3 structure. whereas there are 21 isotropic non-zero components at rank-4 of both structures and 20 and 8 non-zero anisotropic components at rank-4 surface and bulk perovskite. the contribution of 2nd order total polarization only occurs in anisotropic while for 3rd order, polarization isotropic and anisotropic contributing to total polarization