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 (MAPbI3, MAPb(Br0.5Cl0.5)3, MAPb(Br0.05Cl0.95)3, FAPbBr3, FA0.9Cs0.1PbI2.8Br0.2, MA=methylammonium and FA=formamidinium) and all-inorganic (CsPbBr3) 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.

The electronic structure of Mn in the diluted magnetic semiconductor ͑Ga,Mn͒As was studied by means of electronic and spin-flip Raman scattering. The Mn ion was found to manifest itself in three different electronic configurations: ͑i͒ neutral Mn acceptor, i.e., Mn 3d 5 inner-shell electrons with a weakly bound valence band hole, ͑ii͒ ionized Mn acceptor, i.e., 3d 5 state, and ͑iii͒ neutral Mn in the 3d 4 electronic configuration. The latter state undergoes a crystal-field splitting and a Jahn-Teller effect. The energy separation between the optical dipole active sublevels of the 5 T 2 ground state is directly measured in the dynamic Jahn-Teller-effect regime. The Mn 3d 4 state is assumed to play an important role for the ferromagnetism observed in diluted ͑Ga,Mn͒As.

Voltage control of ferromagnetism on the nanometer scale is highly appealing for the development of novel electronic devices with low power consumption, high operation speed, reliable reversibility and compatibility with semiconductor technology. Hybrid structures based on the assembly of ferromagnetic and semiconducting building blocks are expected to show magnetic order as a ferromagnet and to be electrically tunable as a semiconductor. Here, we demonstrate the electrical control of the exchange coupling in a hybrid consisting of a ferromagnetic Co layer and a semiconductor CdTe quantum well, separated by a thin non-magnetic (Cd,Mg)Te barrier. The electric field controls the phononic ac Stark effect—the indirect exchange mechanism that is mediated by elliptically polarized phonons emitted from the ferromagnet. The effective magnetic field of the exchange interaction reaches up to 2.5 Tesla and can be turned on and off by application of 1V bias across the heterostructure.

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The exchange interaction between magnetic ions and charge carriers in semiconductors is considered as prime tool for spin control. Here, we solve a long-standing problem by uniquely determining the magnitude of the long-range p−d exchange interaction in a ferromagnet-semiconductor (FM-SC) hybrid structure where a 10 nm thick CdTe quantum well is separated from the FM Co layer by a CdMgTe barrier with a thickness on the order of 10 nm. The exchange interaction is manifested by the spin splitting of acceptor bound holes in the effective magnetic field induced by the FM. The exchange splitting is directly evaluated using spin-flip Raman scattering by analyzing the dependence of the Stokes shift ∆S on the external magnetic field B. We show that in strong magnetic field ∆S is a linear function of B with an offset of ∆ pd = 50 − 100 µeV at zero field from the FM induced effective exchange field. On the other hand, the s − d exchange interaction between conduction band electrons and FM, as well as the p − d contribution for free valence band holes, are negligible. The results are well described by the model of indirect exchange interaction between acceptor bound holes in the CdTe quantum well and the FM layer mediated by elliptically polarized phonons in the hybrid structure.