They are the notes that are based on a single-source like a paper, or a book. They are taken in the context of that source and not in the context of my own system of beliefs. This allows me the quickly recover the original idea of the authors, the hypotheses under which they were operating, experimental conditions, etc.
In my approach to a digital garden , having atomic notes became very useful to make them easily linkeable ( notes should be concept-based ). Creating explicit literature notes allows me to quickly recover the context from which a conclusion was drawn even if it fits multiple different branches of thought.
In The Luhmann method there's a type of note called the bibliographic note, that should be used to keep track of all the notes that derived from a single source and could have been stored at different locations within the Zettelkasten. For digital storage this type of note is irrelevant, since a quick search of the source's identifier (such as: [ @carattino2018 Gold Nanoparticles as Absolute Nanothermometers ]) yields the exact same information.
Maybe relevant: [[§ how i take notes of papers]]
These are the other notes that link to this one.