A Theory for the High-T c Cuprates: Anomalous Normal-State and Spectroscopic Properties, Phase Diagram, and Pairing

Abstract

A theory of highly correlated layered superconducting materials is applied for the cuprates. Differently from an independent-electron approximation, their low-energy excitations are approached in terms of auxiliary particles representing combinations of atomic-like electron configurations, where the introduction of a Lagrange Bose field enables treating them as bosons or fermions. The energy spectrum of this field accounts for the tendency of hole-doped cuprates to form stripe-like inhomogeneities. Consequently, it induces a different analytical behavior for auxiliary particles corresponding to “antinodal” and “nodal” electrons, enabling the existence of different pairing temperatures at T ∗ and T c . This theory correctly describes the observed phase diagram of the cuprates, including the non-Fermi-liquid to FL crossover in the normal state, the existence of Fermi arcs below T ∗ and of a “marginal-FL” critical behavior above it. The qualitative anomalous behavior of numerous physical quantities is accounted for, including kink- and waterfall-like spectral features, the drop in the scattering rates below T ∗ and more radically below T c , and an effective increase in the density of carriers with T and ω, reflected in transport, optical and other properties. Also is explained the correspondence between T c , the resonance-mode energy, and the “nodal gap”.