Optical transitions in MnGa2Se4

The dependence of the absorption coefficient on incident photon energy in a MnGa2Se4 single crystal has been investigated in the temperature range 110-295 K. Using group-theory analysis of the electron state symmetry and comparison of the symmetry of the energy spectrum of MnGa2Se4 and its isoelectronic analogs, a conclusion about the character of optical transitions has been drawn. It is shown that the features observed at 2.31 and 2.45 eV are related to the intracenter transitions (6) A (1) (1) -> (4) T (2)((4) G) and (6) A (1) (2) -> (4) T (2)((4) G). The (6) A (1) state is split by the crystal field.