  Three-dimensional reconstruction of atomic structure, known as atomic
electron tomography (AET), has found increasing applications in materials
science. The AET has been limited to very small nanoparticles due to the
challenges of obtaining accurate atomic positions for large objects, for which
the projection approximation generally assumed in AET is no longer valid due to
the evolution of the electron probe along the beam direction. To address these
challenges, we have developed a method that represents atoms as local orbitals
and implements a depth-dependent probe-object interaction. Compared to
conventional tomographic methods, the accuracy of atomic positions is improved
by a factor of three and provides a solution for the tomographic reconstruction
of large objects.
