Optical properties of LaTe₂ and CeTe₂

The reflectivity spectra for the single crystals of LaTe₂ and CeTe₂ are measured at several temperatures in the photon energy range from 2 meV to 10.78 eV. The optical conductivity spectra are obtained by the Kramers-Kronig transformation of the reflectivity spectra. The majority of structures in these spectra seem to be due to the optical interband transitions from the valence p-band to the conduction 5d-bands. The 5d-band is expected to be splitted into several bands through the strong crystal field. The two peaks observed at about 2 and 5.8 eV in CeTe₂ seem to be due to the transitions from the occupied 4f-state to the 5d-bands. The 4f level is thought to be about 1 eV below the Fermi level.