The Landé factors of electrons and holes in lead halide perovskites: universal dependence on the band gap.

The Landé or g-factors of charge carriers are decisive for the spin-dependent phenomena in solids and provide also information about the underlying electronic band structure. We present a comprehensive set of experimental data for values and anisotropies of the electron and hole Landé factors in hybrid organic-inorganic (MAPbI 3 , MAPb(Br 0.5 Cl 0.5 ) 3 , MAPb(Br 0.05 Cl 0.95 ) 3 , FAPbBr 3 , FA 0.9 Cs 0.1 PbI 2.8 Br 0.2 , MA=methylammonium and FA=formamidinium) and all-inorganic (CsPbBr 3 ) lead halide perovskites, determined by pump-probe Kerr rotation and spin-flip Raman scattering in magnetic fields up to 10 T at cryogenic temperatures. Further, we use first-principles density functional theory (DFT) calculations in combination with tight-binding and k ⋅ p approaches to calculate microscopically the Landé factors. The results demonstrate their universal dependence on the band gap energy across the different perovskite material classes, which can be summarized in a universal semi-phenomenological expression, in good agreement with experiment.