Fermi surface is on Wikipedia: https://en.m.wikipedia.org/wiki/Fermi_surface https://en.m.wikipedia.org/wiki/Fermi_surface Turns out it's not a super esoteric

Fermi surface is on Wikipedia: https://en.m.wikipedia.org/wiki/Fermi_surface https://en.m.wikipedia.org/wiki/Fermi_surface Turns out it's not a super esoteric concept. It is a "map of where the electrons are", but (and of course the uni PR won't tell you this) it's not a literal position map, it's a map in momentum space. And like you say, it's focused on the highest energy electrons. So it's really saying how the highest energy electrons are distributed in momentum space.