Brief Perspective of High-Temperature Superconductivity in the Cuprates: Strong Correlations Combined with Superexchange Match Experiment

Abstract

High-temperature superconductivity encompasses the cuprates, nickelates, iron pnictides, and LaH_x compounds. The first three groups of compounds involve in the pairing electrons, which are strongly to moderately correlated, whereas in the last class of systems specific phonon excitations. In this overview, we concentrate first on the (semi)quantitative theory of high-T_C superconductivity in the cuprates based on our original vibrational approach beyond the renormalized mean-field theory. The model we mainly explore is the t–J–U model containing superexchange (kinetic exchange) combined with strong interelectronic correlations. Selected equilibrium and dynamic–excitation properties are analyzed briefly. General questions regarding the pseudogap and two-dimensional character of those systems are raised.