Antiferromagnetic order and high-temperature superconductivity

Abstract

The nearly half-filled Hubbard model with strong on-site repulsion is used as a model for the recently discovered copper oxide high-temperature superconductors. The onset of superconductivity upon doping the half-filled lattice of La${}_2{}^{}{}_{}{}^{}\mathrm{Cu}$ ${\mathrm{O}}_4$ is explained in terms of the Bose-Einstein condensation of effective mass $O\left(m_e\right)$. These holes move freely over an antiferromagnetic background. The mechanism is very different from the BCS mechanism. A fit to data is obtained by adjusting the interplane hopping amplitude, which turns out to be extremely small, though necessary.