Ultrahigh vacuum STM/STS studies of the Bi-O surface in Bi2Sr2CuOy single crystals

Scanning tunneling microscopic and spectroscopic studies were made on cleaved of Bi2Sr2CuOy single crystals using an ultrahigh-vacuum scanning tunneling microscope (UHV-STM). The modulation structures of the BiO surface were observed at room temperature with atomic resolution. The tunneling spectra showed electronic gap structures similar to those observed for the BiO surface of superconducting Bi2212 single crystals. This suggests that superconductivity is not directley related to the electronic structure observed in the BiO plane.