  Three-dimensional charge density maps computed by first-principles methods
provide information about atom positions and the bonds between them, data which
is particularly valuable when trying to understand the properties of point
defects, dislocations, and interfaces. This letter presents a method by which
3-dimensional maps of the electrostatic potential, related to the charge
density map by the Poisson equation, can be obtained experimentally at 0.1 nm
resolution or better. This method requires data acquired by holographic
transmission electron microscopy (TEM) methods such as off-axis electron
holography or focal series reconstruction for different directions of the
incident electron beam. The reconstruction of the 3-dimensional electrostatic
(and absorptive) potential is achieved by making use of changes in the
dynamical scattering within the sample as the direction of the incident beam
varies.

Materials Science