Limit of atomic-resolution-tomography reconstruction of amorphous nanoparticles

Three-dimensional atomic structure is routinely determined for periodic crystals. However, extending such analysis to amorphous materials remains a substantial challenge, despite the scientific and technological importance^1,2. In this context, a recent report describing the three-dimensional structure determination of an amorphous solid using atomic-resolution electron tomography (AET) is truly remarkable³. If validated, such an analysis would be groundbreaking. Here we address this issue and investigate whether and when AET can identify all or most atoms in an amorphous nanoparticle. By simulating AET, we reveal limitations on the structural and chemical information AET can determine from noisy electron images. For monoatomic nanoparticles, the structure can be determined with an atomic-position accuracy of tens of picometres under stringent fluence, sampling and projection requirements. For multi-element amorphous nanoparticles, chemical identification resolution is determined by noise and experimental sampling. Heavier atoms are more easily resolved than lighter ones, and large chemical analysis uncertainties emerge when atomic peak and background intensities overlap. Using these insights, we delineate nanoparticle size, composition, electron fluence and image sampling requirements for AET. The results serve as a benchmark for future experiment design and demonstrate a viable approach for amorphous structure determination validation using AET.