Electron/proton transfer reactions and superconductivity: The role of hydrogen in lanthanum copper oxide


  • This work was supported by the Bundesministerium für Forschung und Technologie and the Deutsche Forschungsgemeinschaft.


Communication: Is lanthanum copper oxide really lanthanum copper oxide? Evidence is presented showing that the conventionally prepared semiconductor La2CuO4, which has been the starting material in many studies of the high-Tc superconducting copper oxides, is in fact a nonstoichiometric oxide hydroxide (La1.95CuO3.86(OH)0.14). It is also shown that the conversion of the semiconducting phase to the superconducting phase by anodic oxidation does not proceed via the insertion of oxygen into the La2CuO4 but rather over an electron/proton transfer process.