Determining the three-dimensional atomic structure of an amorphous solid

Abstract

Amorphous solids such as glass are ubiquitous in our daily life and have found broad applications ranging from window glass and solar cells to telecommunications and transformer cores 1,2 . However, due to the lack of long-range order, the threedimensional (3D) atomic structure of amorphous solids have thus far defied any direct experimental determination 3-12 . Here, using a multi-component metallic glass as a model, we advance atomic electron tomography to determine its 3D atomic positions and chemical species with a precision of 21 picometer. We quantify the short-range order (SRO) and medium-range order (MRO) of the 3D atomic arrangement. We find that although the 3D atomic packing of the SRO is geometrically disordered, some SROs connect with each other to form crystal-like

Capturing 3D atomic defects and phonon localization at the 2D heterostructure interface

“…Drift correction was applied to each image as described elsewhere (17)(18)(19)(20). At each tilt angle, 10 images were registered, and the remaining 9 images were aligned to the first image with cross correlation to subpixel precision.…”

“…The traced 3D atomic coordinates and chemical species were refined by a gradient descent method as described elsewhere (17)(18)(19)(20). The 3D atomic coordinates in each model were refined by minimizing the error between the experimental images and those calculated from the model.…”

“…Second, nine sets of 12 images with the experimental tilt angles were calculated from the atomic models. An R 1 factor was computed between measured and calculated images (17)(18)(19)(20). By comparing the R 1 factor among the nine cases, the one with the smallest error R 1 was chosen and updated in the atomic model.…”

“…However, real heterointerfaces neither have perfect crystal lattices nor are in the minimum energy states. Here, using a MoS 2 -WSe 2 lateral heterojunction as a model, we applied atomic electron tomography (AET) (16)(17)(18)(19)(20) to determine the 3D atomic coordinates and crystal defects at the heterointerface with picometer precision. We observed various crystal defectsincluding vacancies, substitutional defects, bond distortion, and atomic-scale ripples-and quantitatively characterized the 3D atomic displacements and full strain tensor across the heterointerface.…”

Advances and Applications of Atomic-Resolution Scanning Transmission Electron Microscopy

“…Atomic-resolution electron tomography, conducted via 4D electron microscopy, significantly expands the application of this method to studying a plethora of materials problems including early-stage nucleation of crystals (Zhou et al, 2019). Yang et al (2021) extended this powerful approach to determining the 3D atomic positions of an amorphous solid. The authors studied the short-range and medium-range order (SRO and MRO) in a multi-component glass-forming alloy.…”