Spin-orbit coupling effects in CdGa2Se4:Co2+ single crystals

Single crystals of CdGa₂Se₄:Co²⁺ were grown by the chemical transport reaction method using iodine as a transporting medium. The optical absorption peaks observed at 4132, 4332, 5970, 6329, 12 903, and 13 793 cm^-1 at 292 K can be explained in terms of the electronic transitions of Co²⁺ ion in S₄ symmetry. The crystal-field parameter Dq and the Racah parameter B were found to be 413 and 455 cm^-1, respectively. Also the absorption spectrum of CdGa₂Se₄:Co²⁺ single crystals obtained at 77 K in the 700-800-nm region was analyzed using S₄ symmetry along with spin-orbit coupling effects.