SPECTROSCOPIC STUDY OF THE CUO CHAINS IN YBA2CU3O7-X

We interpret our previously published results obtained using a techniq ue called current-imaging tunneling spectroscopy (CITS) to study the d etailed electronic structure of the CuO chains in the high-temperature superconductor YBa2Cu3O7-x near the Fermi level. Our CITS data compri se sequences of 32 simultaneously obtained images taken at bias voltag es ranging from -78 to 72 mV. Cross sections of the CITS data, normali zed-conductance analysis, and logarithmic-derivative analysis allow us to examine in detail the behavior of electronic modulations along the CuO chains and the energy gap in the CuO chains of YBa2Cu3O7-x. This new analysis lends a strong foundation to our previous interpretation of the CITS data [H. L. Edwards et al., Phys. Rev. Lett. 75, 1387 (199 5)]. (C) 1996 American Vaccum Society.