Dielectric Function Spectra and Intraband Density-of-States in TlSe

Room temperature spectroellipsometric study of TISe was performed in the photon energy region 1.5-4.6eV. The tensor components of the dielectric function spectrum of TlSe were obtained. Interband density-of-states (DOS) derived from XX (YY) and ZZ components of the obtained dielectric function spectrum was then compared with the calculated intraband DOS, taking into account for selection rules and transition probabilities. It is found that contribution of the interband optical transitions in Γ, T and N points quite plausibly explains main structures in the obtained dielectric function spectra. However, some structures cannot be explained due to optical transitions in these symmetry points. A corresponding assignment is given and discussed.