Metals and Superconductors

In a class of materials known as strongly correlated electron systems, the standard model of electrons in solids breaks down because strong electronic interactions are present. When strong enough, this interaction forces electrons, which in ordinary metals behave as delocalised waves, to localise and behave as particles. Those materials show a luxuriant array of fascinating new states of matter in which magnetic, charge, orbital and structural orders compete for the ground state.