Magnetoreflectivity study of excitons in Zn_1−xFe_xSe epilayers (abstract)

We have performed a magnetoreflectivity study of excitons in epilayers of the diluted magnetic semiconductor Zn_1−xFe_xSe. The samples were grown by molecular‐beam epitaxy on GaAs (100) substrates to a typical thickness of 1 μm. Using both Faraday and Voigt geometries and magnetic spin splittings of the conduction and valence bands. The band splitting was found to be linear in magnetic field B and B<6 T. We measure effective g factors of 33.4 and 28.3 for the conduction and valence bands, respectively. For fields B>6 T, deviations were observed. The band spin splitting was also studied as a function of temperature at constant fields. At low temperatures, the spin splitting is independent of temperature. These data are in agreement with previous magnetization studies¹ which showed that ZnFeSe, unlike Mn‐based diluted magnetic semiconductors, exhibits Van Vleck paramagnetism. The temperature study of the band splitting allowed a determination of the crystal field splitting.