title: A study of charge distribution in Bi2Sr2CaCu2O8+delta superconductors using novel electron-diffraction and imaging techniques.
abstract: We report our study of the distribution of valence electrons in Bi2Sr2CaCu2O8+delta high-temperature superconductors using novel electron-diffraction and imaging techniques. The former method was based on quantitative analyses of the diffraction intensity of many reflections as a function of crystal thickness to determine, with an unprecedented accuracy, the Fourier components of the electron distribution in Bi2Sr2CaCu2O8+delta. The latter was based on examining the effect of charge transfer on many-beam imaging by comparing the observed and calculated low- and high-resolution images of long-period displacive and charge modulation of the cuprate. Our study demonstrates that fast electrons have greater sensitivity than X-rays to valence electrons distribution at small scattering angles, and that electron microscopy is a powerful tool in revealing charge distribution in materials.