Using dynamically scattered electrons for 3-dimensional potential reconstruction

TL;DR

This paper introduces a method to experimentally reconstruct 3D electrostatic potential maps of materials at sub-nanometer resolution using holographic TEM techniques, enabling detailed analysis of atomic structures and defects.

Contribution

It presents a novel approach combining holographic TEM data from multiple beam directions to reconstruct 3D electrostatic potentials, advancing beyond previous 2D or less precise methods.

Findings

Achieves 0.1 nm resolution in 3D potential maps.

Utilizes changes in dynamical scattering with beam direction.

Applicable to studying atomic-scale defects and interfaces.

Abstract

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.