A theory of superconductivity in cuprates

Abstract

A microscopic theory of superconducting pairing mediated by antiferromagnetic (AFM) exchange and spin-fluctuations is developed within the effective p-d Hubbard model for the CuO2 plane. It is proved that retardation effects for AFM exchange interaction are unimportant and result in pairing of all electrons in the conduction band and high Tc proportional to the Fermi energy. The spin-fluctuations caused by the kinematic interaction give an additional contribution to the d-wave pairing. Tc dependence on the hole concentration and lattice constants (or pressure) is studied. Small oxygen isotope shift of Tc is explained. The data are compared with the results for the t-J model.

Keywords

• high-temperature superconductivity
• strong electron correlations
• Hubbard model
• antiferromagnetic exchange interaction
• spin-fluctuations