Surface Chemical Binding States of NO-Intercalated La<sub>1.5</sub>Ba<sub>0.5</sub>SrCu<sub>2</sub>O<sub>6-δ</sub>

The surface chemical binding states of NO-intercalated La1.5Ba0.5SrCu2O6-δ were investigated by X-ray photo-electron spectroscopy (XPS) analysis. The N1s XPS spectra suggested the occurrence of surface adsorption of NO2- and NO3- groups. The chemical shift of the Cu2p XPS peak indicated decreasing hole concentrations at the level of O2p with NO intercalation in contrast to the case of LaBaSrCu2O6-δ. In addition, the surface intercalation of NO-produced a chemical shift of the Ba3d and Sr3d XPS peaks. These results suggested that the Ba content affected the surface groups on the cuprates.