Diffusion Distribution Model for Damage Mitigation in Scanning Transmission Electron Microscopy

TL;DR

This paper introduces a mathematical diffusion model for understanding and mitigating electron beam damage in STEM, enabling optimized sampling strategies to reduce damage during atomic-scale material imaging.

Contribution

It develops an explicit diffusion process model for STEM damage and proposes a framework for designing diffusion-controlled sampling strategies to minimize damage.

Findings

Numerical simulations show variability in diffusion distribution across STEM configurations.

The framework can guide the design of experiments to minimize beam damage.

Analytical models help understand damage accumulation in STEM imaging.

Abstract

Despite the widespread use of Scanning Transmission Electron Microscopy (STEM) for observing the structure of materials at the atomic scale, a detailed understanding of some relevant electron beam damage mechanisms is limited. Recent reports suggest that certain types of damage can be modeled as a diffusion process and that the accumulation effects of this process must be kept low in order to reduce damage. We therefore develop an explicit mathematical formulation of spatiotemporal diffusion processes in STEM that take into account both instrument and sample parameters. Furthermore, our framework can aid the design of Diffusion Controlled Sampling (DCS) strategies using optimally selected probe positions in STEM, that constrain the cumulative diffusion distribution. Numerical simulations highlight the variability of the cumulative diffusion distribution for different experimental STEM configurations. These analytical and numerical frameworks can subsequently be used for careful design of 2- and 4-dimensional STEM experiments where beam damage is minimised.