Cu 2p-1s X-Ray Emission Spectroscopy Of Mineral Tetrahedrite Cul(2)Sb(4)S(13)

The electronic structure of mineral tetrahedrite Cu12Sb4S13 showing a metal-semiconductor transition (MST) at T-MST = 85 K has been investigated by means of Cu 1s x-ray absorption spectroscopy with the partial fluorescence yield mode (PFY-XAS) and Cu 2p-1s x-ray emission spectroscopy (XES). Remarkable changes are detected in both the PFY-XAS and XES spectra on cooling across T-MST. The changes in the spectra indicate that the unoccupied Cu 3d and 4p densities of states (DOS) shift away from the Fermi energy (EF). We conclude that the MST of Cu12Sb4S13 is associated with the decrease of the Cu 3d DOS at E-F.