[WaltYoder]

I am still confused. Are these made of quarks? Electrons? Atoms? Ions?

All the article says is "a new material made from indium arsenide and aluminum".

[sightbroke]

https://en.wikipedia.org/wiki/Fermion

> Fermions have a half-odd-integer spin (spin 1/2 , spin 3/2 , etc.) and obey the Pauli exclusion principle.

> These particles include all quarks and leptons and all composite particles made of an odd number of these, such as all baryons and many atoms and nuclei

I this it's a way to describe a set of particles or "objects" with certain properties.