Angstrom-beam electron diffraction of amorphous materials

We have developed an Angstrom-beam electron diffraction (ABED) technique for structure characterization of amorphous materials using a state-the-of-art spherical aberration-corrected scanning transmission electron microscope. The focused electron beam with a diameter of ~ 0.4 nm, comparable to the size of short range order in glasses, enables us to directly detect local atomic structure of disordered materials in a diffraction mode. In this paper we briefly introduce the basic principle of ABED and preliminary applications in structural characterization of metallic glasses and oxide glasses. We also discuss the effect of sample thickness and the method to study medium range order of glassy materials using ABED.