Spin texture as polarization fingerprint of halide perovskites

Halide perovskites are perceived to be a promising class of materials for optoelectronics, spin orbitronics, and topological electronics due to the presence of strong spin-orbit coupling and polarization field. Here, we develop a Hamiltonian using quasidegenerate perturbation theory to describe polarization field driven band structures and unique topological phases such as Dirac semimetallic rings for a universal class of halide perovskites including both inorganic and hybrid members. The spin textures obtained through this theoretical model captures minute effects of polarization and hence can be used as a modern tool to determine the polarization field directions which have a significant influence on spin orbitronics. The analysis brings out the concepts of hybrid spin textures intermixing the effects of valence and conduction bands under topological quantum phase transitions and spin texture binaries where alignment of the spins are reversed between domains in the momentum space with sharp boundaries. The results are validated through density-functional calculations.