Evidence for a metallic--like state in the T=0 K phase diagram of a high temperature superconductor

TL;DR

This paper investigates how a phenomenological pseudogap influences the zero-temperature phase diagram of high-temperature superconductors with d-wave symmetry, revealing a possible metallic-like state and bosonic degrees of freedom at low densities.

Contribution

It demonstrates that the pseudogap is crucial for the emergence of a metallic-like state in the phase diagram and explores the transition to bosonic behavior at high attractive interactions.

Findings

Presence of a pseudogap is essential for a metallic-like state.

Bosonic-like degrees of freedom emerge at low densities and high interactions.

Results are relevant for understanding underdoped high-temperature superconductors.

Abstract

We examine the effects of a phenomenological pseudogap on the T=0 K phase diagram of a high temperature superconductor within a self-consistent model which exhibits a d-wave pairing symmetry. At the mean-field level the presence of a pseudogap in the normal phase of the high temperature superconductor is proved to be essential for the existence of a metallic--like state in the density versus interaction phase diagram. In the small density limit, at high attractive interaction, bosonic--like degrees of freedom are likely to emerge. Our result should be relevant for underdoped high temperature superconductors, where there is a strong evidence for the presence of a pseudogap in the excitation spectrum of the normal state quasiparticles.