Microscopic electronic inhomogeneity in the high-Tc superconductor Bi2Sr2CaCu2O(8+x)

We report the presence of an electronic inhomogeneity in Bi2Sr2CaCu2O(8+x) on the basis of observations using scanning tunnelling microscopy and spectroscopy. The inhomogeneity is manifested as spatial variations in both the local density of states spectrum and the superconducting energy gap. These variations are correlated spatially and vary on the surprisingly short length scale of about 14 A. Our analysis suggests that this inhomogeneity is a consequence of proximity to a Mott insulator resulting in poor screening of the charge potentials associated with the oxygen ions left in the BiO plane after doping, and is indicative of the local nature of the superconducting state. (Author)