Stochastic ion emission perturbation mechanisms in atom probe tomography: Linking simulations to experiment

Field evaporation in atom probe tomography (APT) includes known processes related to surface migration of atoms, such as the so-called roll-up mechanism. They lead to trajectory aberrations and artifacts on the detector. These processes are usually neglected in simulations. The inclusion of such processes is crucial for providing reliable models for the development and verification of APT reconstruction algorithms, a key part of the whole methodology. Here, we include stochastic lateral velocity perturbations and a roll-up mechanism to simulations performed using the Robin-Rolland model. By comparing with experimental data from Al and Ni systems, we find the stochastic perturbation energy distributions that allow us to very accurately reproduce the detector patterns seen experimentally and thus greatly improve the accuracy of the simulations. We also explore the possible causes of remaining discrepancies between the experimental and simulated detector patterns.