Magneto-optical study under pulsed high magnetic fields of β- FeSi2 single crystals grown by a chemical vapor transport method

We measured the photoluminescence (PL), the optical absorption and the magneto-optical absorption of β- FeSi2 single crystals which were fabricated by a chemical vapor transport method. The characteristic 0.8 eV-PL bands of β- FeSi2 thin films were not observed in our single crystals. However, we found new two PL lines (0.717 and 0.737 eV) and new two absorption peaks (0.858 and 0.909 eV) at low temperatures. All the samples which were measured in this study were classified into two groups according to the absorption peak energies. The two types of samples showed different absorption energies, but the magnetic field dependencies of the energy shifts are quite the same. Furthermore, the evaluated effective g factor is about 4 for both types of samples.