Crossover from a pseudogap state to a superconducting state

TL;DR

This paper proposes a theoretical model explaining the transition from a pseudogap state to superconductivity in cuprates, emphasizing the role of electronic structure and pairing regions, and linking gap symmetry to high-temperature superconductivity.

Contribution

It introduces a new explanation for the pseudogap-superconductor crossover based on the electronic structure and pairing regions in cuprates, highlighting the importance of non-s wave gap symmetry.

Findings

Cooper pairs form first in the antinodal region, causing the pseudogap.

Coherent pairs form in the nodal region, leading to superconductivity.

Non-s wave gap symmetry favors high-temperature superconductivity.

Abstract

On the basis of our calculation we deduce that the particular electronic structure of cuprate superconductors confines Cooper pairs to be firstly formed in the antinodal region which is far from the Fermi surface, and these pairs are incoherent and result in the pseudogap state. With the change of doping or temperature, some pairs are formed in the nodal region which locates the Fermi surface, and these pairs are coherent and lead to superconductivity. Thus the coexistence of the pseudogap and the superconducting gap is explained when the two kinds of gaps are not all on the Fermi surface. It is also shown that the symmetry of the pseudogap and the superconducting gap are determined by the electronic structure, and non-s wave symmetry gap favors the high-temperature superconductivity. Why the high-temperature superconductivity occurs in the metal region near the Mott metal-insulator transition is also explained.