Fermi surface

A Fermi surface is an abstract shape representing the distribution of electrons in a metal or solid material at the highest energy level they occupy at absolute zero temperature. It is a boundary in momentum space that separates filled electron states from empty ones. The shape and size of this surface reveal important properties of the material, such as electrical conductivity, magnetism, and how electrons respond to external influences. Essentially, it helps scientists understand how electrons behave inside a material, impacting its overall physical characteristics.