X-Ray Photoemission Spectroscopy of Nd_2-xCe_xCuO_4-y and La_2-xSr_xCuO₄

Abstract

We have measured the Cu 2 p and O 1 s X-ray photoemission spectra of the high- T c superconductors Nd 2- x Ce x CuO 4- y and La 2- x Sr x CuO 4 , and the copper oxides CuO and Cu 2 O. The Cu 2 p spectra of superconductors show features similar to those of CuO with divalent Cu ions. For Nd 2- x Ce x CuO 4- y , the intensity ratio of the satellite to the main peaks decreases with increasing Ce content. The O 1 s spectra exhibit a single-peaked structure and are insensitive to whether either electron or hole is doped.