Near-Isotropic Sub-{\AA}ngstrom 3D Resolution Phase Contrast Imaging Achieved by End-to-End Ptychographic Electron Tomography

TL;DR

This paper introduces an end-to-end ptychographic electron tomography method that achieves near-isotropic sub-angstrom 3D resolution, overcoming traditional limitations like the missing wedge effect in electron microscopy.

Contribution

The paper presents a novel end-to-end multi-slice ptychographic tomography algorithm that directly reconstructs 3D electrostatic potential volumes from 4D-STEM data, compensating for missing wedge effects.

Findings

Successfully reconstructed 3D atomic structures of nanoparticles.

Achieved sub-angstrom resolution in experimental reconstructions.

Demonstrated effectiveness with both simulated and real data.

Abstract

Three-dimensional atomic resolution imaging using transmission electron microscopes is a unique capability that requires challenging experiments. Linear electron tomography methods are limited by the missing wedge effect, requiring a high tilt range. Multislice ptychography can achieve deep sub-{\AA}ngstrom resolution in the transverse direction, but the depth resolution is limited to 2 to 3 nanometers. In this paper, we propose and demonstrate an end-to-end approach to reconstructing the electrostatic potential volume of the sample directly from the 4D-STEM datasets. End-to-end multi-slice ptychographic tomography recovers several slices at each tomography tilt angle and compensates for the missing wedge effect. The algorithm is initially tested in simulation with a Pt@$\mathrm{Al_2O_3}$ core-shell nanoparticle, where both heavy and light atoms are recovered in 3D from an unaligned 4D-STEM tilt series with a restricted tilt range of 90 degrees. We also demonstrate the algorithm experimentally, recovering a Te nanoparticle with sub-{\AA}ngstrom resolution.