Hi all, I am currently writing a report about superconductors, and am currently reading about how the band gap shows that single electrons are not the charge carriers responsible for superconductivity. However, I was confused when I read that electrons are fermions and as such there are no band gaps. I was wondering if someone could possible explain what this means? As I understand it, there is no band gap in a normal metal, but there is in an insulator since otherwise it would conduct electricity, and there are also energy gaps between the 1s, 2s, 3p orbitals etc. Thanks in advance!