Optical absorption in MnIn2S4 single crystals

Abstract

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 Egd and Egi are found to be −4.84 × 10−4 and −6.33 × 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.