An improved method assigning three-dimensional atomic potentials to multiple slices in exit-wave simulations of Transmission Electron Microscopy

Highlights: • We propose an approach to calculate the potential of atoms projected onto slices via a simple analytical expression. • The potential in 3D distribution is properly projected onto corresponding slices, and the influence of the atomic altitude on the potential assignment is reflected correctly. • A specimen can be sliced extremely thin, and the sliced potential can be calculated in a reciprocal space with no approximations. • Tests conducted with Ba₆Nd₂Ti₄O₁₇ supercell verify the good performance of this new approach. An atomic potential should be assigned to several slices in the multislice method owing to its three-dimensional (3D) distribution. Based on a formula including several Gaussian functions to fit electron atomic scattering factors, a simple analytical expression is proposed to calculate the potential of atoms projected onto multiple slices. The potential in 3D distribution is properly projected onto slices that do not contain the atomic centroid. Thus, the fluctuations in atomic altitude influence the assigning of atomic potentials is considered correctly. The projected potential is calculated in a reciprocal space and involves an accurate 3D atomic position. Tests conducted with a plausible Ag chain verify the good performance of this new approach. The simulated exit wave leaving a complex crystal of Ba₆Nd₂Ti₄O₁₇ demonstrates that the proposed simulation approach is better than the traditional multislice method.