Complex dielectric function for liquid Se-Tl mixtures has been obtained by ellipsometric measurements at temperatures between 300 and 500°C. The optical gap decreases rapidly with increasing Tl-concentration in the low concentration region less than 15 at.% Tl, while it remains nearly constant for higher concentrations up to 40 at.% Tl. A long-standing problem of the discrepancy between the activation energies of the electrical conductivity and thermopower can be resolved by considering the temperature dependence of the energy gap precisely.
ASJC Scopus subject areas
- Physics and Astronomy(all)