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.