Efficient first principles simulation of electron scattering factors for transmission electron microscopy

TL;DR

This paper introduces a fast, ab initio method for simulating electron scattering factors in transmission electron microscopy, improving accuracy over traditional atomistic models while reducing computational demands.

Contribution

The authors develop a new approach to generate electrostatic potentials using projector functions, enabling efficient and accurate electron microscopy image simulations.

Findings

Simulated images closely match experimental data.

Method achieves accuracy comparable to all-electron calculations.

Significantly reduces computational cost for simulations.

Abstract

Electron microscopy is a powerful tool for studying the properties of materials down to their atomic structure. In many cases, the quantitative interpretation of images requires simulations based on atomistic structure models. These typically use the independent atom approximation that neglects bonding effects, which may, however, be measurable and of physical interest. Since all electrons and the nuclear cores contribute to the scattering potential, simulations that go beyond this approximation have relied on computationally highly demanding all-electron calculations. Here, we describe a new method to generate ab initio electrostatic potentials when describing the core electrons by projector functions. Combined with an interface to quantitative image simulations, this implementation enables an easy and fast means to model electron microscopy images. We compare simulated transmission electron microscopy images and diffraction patterns to experimental data, showing an accuracy equivalent to earlier all-electron calculations at a much lower computational cost.