Photoemission Study on Natural Oxidation of Cu₃Au with Synchrotron Radiation

Abstract

We report results of the study on natural oxidation of Cu₃Au(110) with high-resolution x-ray photoemission spectroscopy in conjunction with synchrotron radiation. The clean surface of Cu₃Au(110) is terminated with 50% Au and 50% Cu atoms. After the natural oxidation in the air, Cu atoms segregate on the surface and produces the Cu-oxide. As a result, Au atoms move to the bulk. Au atoms below the oxide reduce the diffusion of O atoms further into bulk and limit the oxide thickness. From the face dependence of natural oxidation, the diffusion of Cu atoms also contribute to the oxide formation.