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

TL;DR

This paper presents a comprehensive theory for high-temperature cuprate superconductors, explaining their anomalous normal-state properties, spectroscopic features, phase diagram, and pairing mechanisms through a correlated electron approach involving auxiliary particles and stripe inhomogeneities.

Contribution

It introduces a novel auxiliary particle framework with a Lagrange Bose field to describe cuprates, capturing their complex phase diagram and spectroscopic phenomena beyond independent-electron models.

Findings

Describes the phase diagram including non-Fermi-liquid to Fermi-liquid crossover.

Accounts for Fermi arcs and marginal-FL behavior above T*.

Explains spectral features like kinks, waterfalls, and carrier density variations.

Abstract

A theory of highly correlated layered superconducting materials isapplied 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 \omega, reflected in transport, optical and other properties. Also is explained the correspondence between T_c, the resonance-mode energy, and the "nodal gap".