Optical absorption in MnIn2S4 single crystals

Optical absorption in MnIn2S4 single crystals has been studied. Direct and indirect optical transitions are found to occur at photon energies of 1.90-2.16 eV in the temperature range of 80-342 K. The temperature dependence of the band gap is determined; its temperature coefficients E (gd) and E (gi) are found to be -4.84 x 10(-4) and -6.33 x 10(-4) eV/K, respectively. The electron-phonon interaction is the main mechanism of the temperature shift of the intrinsic-absorption edge. MnIn2S4 single crystals exhibit anisotropy in polarized light at the absorption edge in the temperature range of 90-190 K; the nature of this anisotropy is explained.