Researchers at the California NanoSystems Institute at UCLA have published a framework for determining the three-dimensional positions and elemental identities of atoms in amorphous materials. Amorphous materials, such as glass, do not have the repeating atomic patterns found in crystals. The team used algorithms to analyze simulated electron-microscope data and assessed how each step affected mapping accuracy.
For amorphous silica, which is the main component of glass, the researchers demonstrated complete accuracy in identifying the three-dimensional positions of silicon and oxygen atoms under favorable imaging conditions. The precision achieved was about seven trillionths of a meter.
Three-dimensional atomic structure determination has traditionally been limited to crystal structures because it relies on averaging repeated patterns. Mapping individual atoms in non-repeating structures has only recently become possible. The UCLA study appears alongside another paper on this topic in Nature.
The research focused on two imaging techniques developed by Jianwei “John” Miao, a professor of physics and astronomy at UCLA. Atomic electron tomography (AET) involves taking multiple images from different angles with an electron beam to reconstruct a 3D map of atoms. Ptychography records patterns of scattered electrons as a focused beam scans a sample and uses algorithms to reconstruct an image without using a physical lens.
To validate their approach, the team used simulated AET and ptychographic data that closely mimic real experiments. Their algorithms addressed errors such as image noise, variations in focus, and atomic vibrations due to temperature. These factors were included in quantum mechanics-based electron scattering simulations. Known constraints like atom types and typical distances between neighboring atoms helped refine the final 3D maps.
Algorithms are expected to improve with advances in programming and hardware, making computational microscopy—including AET and ptychography—a promising tool for 3D atomic imaging. Unlocking the 3D structure of amorphous materials could drive technological innovation and provide new scientific insights.
Glass is one example of an amorphous material widely used across various technologies including ultrathin electronics, solar cells, memory devices, medical equipment, and quantum technologies. Future developments may enable biologists to image individual carbon and nitrogen atoms—elements essential for life—once advances allow their identification alongside those already mapped.
The first author of the study is Yuxuan Liao, a postdoctoral researcher at UCLA. Other contributors include Haozhi Sha, Colum O’Leary, Hanfeng Zhong (all from UCLA), and Yao Yang (a UCLA doctoral alumnus now at Westlake University in China).
“There are no disclosures associated with this research.”
The study was published in Nature.
Funding was provided by STROBE—a National Science Foundation Science and Technology Center—and the U.S. Air Force Office of Scientific Research.
