Electronic structure of thallium copper chalcogenides TlCu2S2 and TlCu2Se2

The electronic band structure is calculated for ternary thallium copper chalcogenides TlCu2S2 and TlCu2Se2. The electronic density of states calculated for these chalcogenides shows fairly good agreement with valence-band X-ray photoemission spectra. The conduction bands are mainly composed of S 3p (or Se 4p) states and have the hole-like Fermi surfaces. These results are consistent with electrical transport properties measured for these chalcogenides.