Real-Space Superconductivity

Superconductivity in solids is caused by dynamic pairing of electrons or holes. In the weak coupling limit, Cooper pairs are localized in momentum space and produce low-temperature superconductivity. In the opposite, strong coupling limit, real-space pairs are formed that Bose-condense and produce high-temperature superconductivity. Superconductivity as a Bose-Einstein condensation of electron pairs was proposed before the BCS theory by a team in Sydney Australia that since has been all but forgotten. In this presentation, I will argue that the real-space pairing theory is still relevant to the ongoing search for room-temperature superconductivity, and that metal-oxide superconductors are in the intermediate regime between the two limits. I will discuss lattice contributions to the pairing interaction and the important roles of lattice dimensionality and strong electron correlations. The rules of real-space superconductivity are formulated in the end.