Optical Reflectivity Spectrum of a CuFeS2 Single Crystal

Critical reflectivity spectra have been measured at room temperature on a single crystal of CuFeS 2 between 0.025 and 6 eV. The experimental results have been used to calculate the optical constants, the dielectric constant and the absorption coefficient. There have been found an absorption band with peaks at 1.0 and 2.1 eV and an absorption edge at approximately 3.2 eV. The band can be assigned to the charge-transfer transition from the valence band to the empty 3d states of Fe, and the edge can be attributed to the commencement of the band to band transition. A schematical energy level diagram for CuFeS 2 is given from the result.