Effects of Ce Doping on Electronic Structures of Ln_2-xCe_xCuO₄ (Ln=Nd, Sm, Eu, Gd) Studied by Core-Level Photoemission Spectroscopy

Abstract

We have investigated the changes in the electronic structures of Ln 2- x Ce x CuO 4 (Ln=Nd, Sm, Eu and Gd) upon Ce doping using core-level X-ray photoemission spectroscopy. For Ln 2- x Ce x CuO 4 , the O 1 s spectra exhibit a single-peaked structure. The energy positions of the O 1 s lines are shifted toward the high binding energy side with increasing Ce concentration. For the Cu 2 p spectra, the intensity ratio of the satellite to the main peaks decreases with increasing Ce concentration. This decrease can be explained by the presence of Cu 1+ under Ce doping.