THE DISCREPANCY BETWEEN MUON SPECTROSCOPY AND SCANNING TUNNELING MICROSCOPY AND PHOTOEMISSION: YBa2Cu3O7 AND Bi2Sr2CaCu2O8

Muon spectroscopy of YBa2Cu3O7 and Bi2Sr2CaCu2O8 produces strong evidence that both materials are s-wave superconductors, while scanning tunneling microscopy (STM) and photoemission data seem to indicate that Bi2Sr2CaCu2O8 in particular has d-wave character. The resolution of this apparent discrepancy is that the CuO2 planes (which are responsible for the d-wave character reported by STM and photoemission) do not superconduct and are different from the superconducting BaO or SrO layers sensed by muons.