Effects of the local structure dependence of evaporation fields on field evaporation behavior

TL;DR

This paper introduces a physics-based model for atom probe tomography that uses density functional theory to better understand atom evaporation, improving the accuracy of 3D reconstructions and spatial resolution insights.

Contribution

It presents a novel modeling framework combining continuum field models with density functional theory for atom evaporation.

Findings

Reproduces experimental evaporation sequences

Enhances understanding of depth resolution limits

Provides a more physical basis for atom probe data analysis

Abstract

Accurate three dimensional reconstructions of atomic positions, and full quantification of the information contained in atom probe tomography data relies on understanding the physical processes taking place during field evaporation of atoms from needle-shaped specimens. However, the modeling framework for atom probe tomography has remained qualitative at best. Building on the continuum field models previously developed, we introduce a more physical approach with the selection of evaporation events based on density functional theory calculations. This new model reproduces key features observed experimentally in terms of sequence of evaporation, desorption maps, and depth resolution, and provides insights into the physical limit for spatial resolution.