FTP, what is this concept in solid-state physics named for an Italian-American physicist?
It was studied for certain high-Tc superconductors by Mesot et. al., who used angle-resolved photoemission spectroscopy to conclude there is a single large one in the materials studied. Another probe sometimes used to study it is the de Haas-van Alphen effect. For free electrons, it is just a sphere, but in crystal lattices it acquires directional dependence. At absolute zero it separates filled from unfilled orbitals.  It is a surface in momentum space with constant energy. FTP, what is this concept in solid-state physics named for an Italian-American physicist?
It was studied for certain high-Tc superconductors by Mesot et.
Fermi surface (prompt on "Fermi")