Optical absorption of MnGa_2S_4 single crystals

摘要

Based on the absorption spectra studies in a wide temperature and wave-lengths region, the peculiarities of the MnGa_9S_4 absorption spectra at 2.49 and 2.65 eV are shown to be attributed to the absorption on intracentered transitions of two-valent ions, Mn~(2+)[~6A_1 ->~4T_2(~4G)] and ~6A_1(~6S)->A_1, ~4E(~4G). The fundamental absorption edge is formed by the direct allowed transitions. The temperature coefficient of the band gap has been determined.