Applications of a versatile modelling approach to 3D atom probe simulations

Area of Science:

• Materials Science
• Computational Physics
• Surface Science

Background:

• Atom Probe Tomography (APT) field emitters require detailed atomic structure modeling.
• Simulating atom evaporation under electric fields is crucial for understanding emitter behavior.

Purpose of the Study:

• To present a flexible simulation approach for modeling arbitrary crystal structures and simulating atom evaporation.
• To analyze field desorption maps and the effects of inhomogeneous evaporation conditions.

Main Methods:

• Utilizing an irregular mesh of Voronoi cells to represent atomic structures (Wigner-Seitz cells).
• Solving the Poisson equation for electric field calculations.
• Calculating field-induced forces to simulate atom evaporation sequences.

Main Results:

• Simulated field desorption maps for various crystal structures (fcc, hcp, sc, bcc) and orientations.
• Demonstrated the impact of inhomogeneous evaporation on emitter apex curvature.
• Analyzed reconstructions of grain boundaries and estimated stress on embedded nanoparticles.

Conclusions:

• The flexible Voronoi cell simulation approach enables accurate modeling of complex atomic structures and evaporation processes.
• The method provides insights into emitter performance, material behavior under stress, and surface phenomena.