Low-energy electron energy loss spectroscopy on Bi2Sr2Can-1CunO2n+4+x (n=1,2)

Electronic structures of the high-Tc superconductor Bi2Sr2Can-1CunO2n+4+x (n=1,2) have been investigated by low-energy electron energy loss spectroscopy (LEELS) in the valence and shallow core electron excitation region. The LEELS spectra are almost independent of the incident electron energy, that is, of probing depth, indicating rather extended electronic states of those materials. It has been also discovered that the existence of Ca layer does not affect the overall spectra so much except in the Ca 3p core electron excitation region. (author)