Electronic structure of CuCr2S4 by XPS, XANES and EXAFS

Electronic environments in carrollite, CuCo2S4, determined by soft X-ray photoelectron and absorption spectroscopy

“…3 near 932 eV kinetic energy would have arisen from Cu 3p photoelectrons, and the peak near 906 eV can be assigned to Co 3s photoelectrons. The Cu 2p spectrum for carrollite was broadly similar in appearance to those obtained by conventional XPS for the thiospinels CuIr 2 S 4 (Matsuno et al, 1997), CuV 2 S 4 (Lu et al, 1996) and CuCr 2 S 4 (Lenglet et al, 1988) insofar as the shape of the background is concerned, including no more than weak excited final state satellites. However, the reported Cu 2p 3/2 binding energy for those thiospinels ranged from 932 to 932.7 eV.…”

“…However, on theoretical and Cu 2p electron spectroscopic grounds, Vaughan and Tossell (1981) expected the Cu oxidation state to approach Cu I . Goodenough (1967) argued that the structurally analogous thiospinel CuCr 2 S 4 was Cu II Cr III 2 S 4 rather than Cu I Cr III Cr IV S 4 as proposed by Lotgering and van Stapele (1967), and in disagreement with Cu I established later by Cu K-edge X-ray absorption spectroscopy (Lenglet et al, 1988).…”

The influence of the concentration of Sb ions onto the local crystal and electronic structures of CuCr2−xSbxS4 (x=0.3, 0.4, 0.5) studied by XANES and EXAFS measurements and LAPW numerical calculations

“…While the magnetic moment agrees well with the result for similar compounds [8,9] the charges must be treated with great caution. When the Cr S chemical bond is not ionic as was suggested before [6][7][8][9], some charge is moved to the region outside spheres (in our case 12.5 electrons). There are, however, two facts that are interesting:…”

“…Additionally, when some of the electronic states move up above the Fermi level they become less occupied. It can be equivalently described as creating holes in the sulfur p-like band what was suggested in previous papers [6,7,9].…”

“…(a) by breaking the magnetic paths Cr 3+ -S-Cr 4+ ; [6][7][8][9]. Since the double exchange and the super exchange are transferred through sulfur atoms, we have chosen to measure the sulfur K X-ray absorption edge as a probe for a local electronic structure.…”