High-temperature superconductivity in cuprates and a Wigner lattice of electron pairs

Abstract

A model of high-temperature superconductivity in cuprates where delocalization of one-dimensional Wigner lattices of electron pairs is responsible for superconductivity is suggested. The milestones of the model are as follows: 1. Symmetric polarization of oxygen ions in the CuO 2 layer by two neighboring copper ions leading to formation of one-electron σ bonds between the ions. 2. Asymmetric polarization of oxygen ions in the electric field around a CuO 2 layer resulting in the excitation of singlet electron pairs of oxygen ions from the 2p z state into a (2p z 3s) state, the singlet nature of the pair being preserved. 3. Lowering of the CuO 2 layer symmetry under doping and formation of quasi-one-dimensional chains of copper and oxygen ions bound by one-electron σ bonds. 4. Formation of one-dimensional Wigner lattices of electron pairs due to a strong Coulomb interaction between these pairs. 5. Formation of delocalized π orbitals along ion chains and delocalization of Wigner lattices of electron pairs at the temperature regarded as the temperature of transition to superconductivity. The model allows one to explain the co-existence of superconductivity and magnetism, orbital ion ordering, the role of local lattice distortions, the stripe structure of the electron density, and a quasi-one-dimensional character of superconductivity.