Density functional theory for superconductors

摘要: In this highlight we review density functional theory for superconductors. This formally exact theory is a generalisation of normal-state density functional theory, which also includes the superconducting order parameter and the diagonal of the nuclear density matrix as additional densities. We outline the formal framework and the construction of approximate exchange-correlation functionals. Several aspects of the theory are demonstrated by some examples: a first application to simple metals shows that weakly and strongly coupled superconductors are equally well described. Calculations for MgB2 with its two gap superconductivity demonstrate the capability to go beyond simple BCS superconductivity. Finally the formalism is applied to aluminium, lithium and potassium under high pressure, describing correctly the experimental behaviour of Al and Li, and predicting fcc-K to become superconducting at high pressures.