A Unified Theory for the Cuprates, Iron-Based and Similar Superconducting Systems: Application for Spin and Charge Excitations in the Hole-Doped Cuprates

摘要

A unified theory for the cuprates and the iron-based superconductors isderived on the basis of common features in their electronic structuresincluding quasi-two-dimensionality, and the large-U nature of the electronorbitals close to E_F (smaller-U hybridized orbitals reside at bonding andantibonding states away from E_F). Consequently, low-energy excitations aredescribed in terms of auxiliary particles, representing combinations ofatomic-like electron configurations, rather than electron-like quasiparticles.The introduction of a Lagrange Bose field is necessary to enable the treatmentsof these auxiliary particles as bosons or fermions. The condensation of thebosons results in static or dynamical inhomogeneities, and consequently in acommensurate or an incommensurate resonance mode. The dynamics of the fermionsdetermines the charge transport, and their strong coupling to theLagrange-field bosons results in pairing and superconductivity. The calculatedresonance mode in hole-doped cuprates agrees with the experimental results, andis shown to be correlated with the pairing gap on the Fermi arcs.