Highly Correlated Electron State and High-Temperature Superconductivity in Iron Pnictides

Abstract

It is shown that the qualitative model of the high-temperature superconductivity suggested earlier for cuprates and doped picene and based on the idea that the valence electron state depends on the character of the chemical bonds they form and on the Coulomb interaction between the electrons is not only confirmed by the experimental data on iron pnictides but is also improved. From the chemical point of view, the high-temperature superconductivity is associated with additional $\pi$ bonding along chains of covalently bonded ions via a delocalized $\pi$ orbital, just like in cuprates. From the physical point of view, as the data on iron pnictides show, the superconductivity is associated with a FeAs layer transition into the state similar to a macroscopic quantum system characterized by a highly correlated electron state, formation of two-dimensional crystals of electron pairs with quantized energy levels, and a strong Coulomb interaction between these crystals. Superconductivity in such a system is accomplished by a two-dimensional Wigner crystal consisting of one-dimensional Wigner crystals formed by bosons, i.e., singlet electron pairs that are in the same quasi-one-dimensional state extending along the ion chain, which corresponds to a delocalized $\pi$ orbital in chemistry. The model applicability to three different classes of materials (cuprates, picene, iron pnictides) indicates that it can prove useful for development of the theory of superconductivity taking into consideraion the highly correlated state of valence electrons and strong Coulomb interactions between the electrons.

18 pages, 9 figures

References in corpus (13)

• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Superconductivity at 27 K in tetragonal FeSe under high pressure
• Pressure-induced volume-collapsed tetragonal phase of CaFe2As2 as seen via neutron scattering
• Proximity of antiferromagnetism and superconductivity in LaO${}_{1-x}$F${}_x$FeAs: effective Hamiltonian from ab initio studies
• A Large Iron Isotope Effect in SmFeAsO1-xFx and Ba1-xKxFe2As2
• Magnetic Order of the Iron Spins in NdOFeAs
• Inverse Iron Isotope Effect on the transition temperature of the (Ba,K)Fe2As2 superconductor
• Spin Ordering in LaOFeAs and Its Suppression in Superconductor LaO0.89F0.11FeAs Probed by Mössbauer Spectroscopy
• Electromagnetic properties and electronic structure of iron-based layered superconductor LaOFeP
• Low-temperature lattice anomaly in LaFeAsO0.93F0.07 probed by x-ray absorption spectroscopy: Evidence for strong electron-lattice interaction
• Absence of an appreciable iron isotope effect on the transition temperature of the optimally doped SmFeAsO_{1-y} superconductor
• Moessbauer and magnetic measurements of superconducting LiFeP
• Highly Correlated Electron State and High-Temperature Superconductivity in Iron Pnictides

Cited by in corpus (1)

• Highly Correlated Electron State and High-Temperature Superconductivity in Iron Pnictides