Observation of local barrier height and electronic structure on cuprate superconductor by STM/STS

Abstract

The local barrier height (LBH) of the Bi2212 (Bi2Sr 2CaCu2O8+δ, Tc=93 K) superconducting single crystal is investigated by using scanning tunneling microscopy / spectroscopy (STM/STS). It is found that the atomically resolved LBH distribution is strongly related with the well-known supermodulation structure of Bi2212 surface. The magnitude of LBH is closely related to the Bi-Bi atomic distance affected by the supermodulation. The comparison with simultaneously obtained conductance spectra shows that there are few correlations between the spatial modulation of gap amplitude and LBH. © 2008 IOP Publishing Ltd.