A unified theory for the cuprates, iron-based and similar superconducting systems: non-Fermi-liquid to Fermi-liquid crossover, low-energy and waterfall anomalies

摘要

A unified theory is outlined for the cuprates, Fe-based, and relatedsuperconductors. Their low-energy excitations are approached in terms ofauxiliary particles representing combinations of atomic-like electronconfigurations, and the introduction of a Lagrange Bose field enables theirtreatment as bosons or fermions. This theory correctly describes the observedphase diagram of the cuprates, including the non-Fermi-liquid to FL crossoverin the normal state, the existence of Fermi arcs below T^* and of "marginal-FL"behavior above it. The anomalous behavior of numerous physical quantities isaccounted for, including kink- and waterfall-like spectral features, the dropin the scattering rates below T^* and more radically below T_c, and aneffective increase in the density of carriers with T and \omega, reflected intransport, optical and other properties. Also is explained the correspondencebetween T_c, the resonance-mode energy, and the increase in the gap below T_c.