Soft X‐ray photoemission spectroscopy of (LnO)CuS (Ln=Ce, Pr, Nd)

Soft x-ray photoemission spectroscopy for layered oxysulfides (LnO)CuS (Ln = Ce, Pr, Nd) has been curried out in the Ln 3d-4f absorption region, to deduce the Ln 4f partial densities of states (DOSs). Only the Ce 4f DOS contributes to the valence-band maximum of (CeO)CuS, and on going from Ln = Ce to Pr, and to Nd, the 4f DOS shifts toward the deeper binding-energy side due to the lanthanide contraction. The Ce 3d photoemission spectrum of (CeO)CuS shows the mixing of Ce3+ and Ce4+ in the ground state. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)