They say it’s a picture of atoms, but what are the atoms: the glowing yellow balls or the entire meatball including the darker red? If it’s the meatballs, then why do some have apparently two nuclei?
Here’s the public press release: https://news.cornell.edu/stories/2021/05/cornell-researchers-see-atoms-record-resolution
Here’s the actual scientific article: https://www.science.org/doi/10.1126/science.abg2533
The pairs of nuclei are two Praseodymium nuclei in close proximity. I base that conclusion on the paper listing figures for measurements of Pr-Pr distances that are much smaller than the separation between other elements in the crystal. The small/faint dots are Oxygen nuclei and the bright lone dots are Scandium nuclei.
As to why the crystal lattice is arranged that way, I’m not sure.