X-ray emission spectra and electronic structure of CuIr 2S 4 and CuIr 2Se 4

Abstract

Measurements of X-ray emission spectra of Cu L 2,3, S Kβ 1,3, S L 2,3 and Ir N 6,7 in CuIr 2S 4 and CuIr 2Se 4 have been performed. These measurements probe the partial Cu 3 d 4 s, S 3 p, S 3 s 3 d and Ir 5 d density of states, respectively, in the valence band. The excitation energy dependence of the Cu L 2,3 X-ray emission (XES) in CuIr 2S 4 and CuIr 2Se 4 has been measured using tunable synchrotron radiation. These measurements enabled us to obtain Cu L 3 XES free from overlapping Cu L 2 XES and high-energy satellites. These spectra reproduce the distribution of Cu 3 d-states in the valence band. X-ray emission spectra of constituents atoms of CuIr 2S 4 and CuIr 2Se, were adjusted to the binding energy scale using XPS binding energies of core levels and compared with band structure calculations and valence band spectra obtained by UPS and XPS. From these measurements one concludes that Cu 3 d-states are less mixed with Ir 5 d-states in CuIr 2Se 4 and their contribution to the density of states at the Fermi level is smaller than that of CuIr 2S 4.