The Superconducting and Pseudogap Phase Diagram of High-Tc Cuprates

TL;DR

This paper derives analytic expressions for the critical temperatures of superconducting and pseudogap phases in high-Tc cuprates, aligning well with experimental data and providing insights into their phase diagram and potential ways to enhance Tc.

Contribution

It presents a unified theoretical framework explaining the phase diagram of high-Tc cuprates, including the symmetry and interactions of SC and PG phases, with predictions matching experimental results.

Findings

Analytic expressions match experimental Tc data for single-layer cuprates.

Optimal doping occurs when the chemical potential vanishes.

The model explains the growth of Tc with the number of layers in cuprates.

Abstract

We derive analytic expressions for the critical temperatures of the superconducting (SC) and pseudogap (PG) phases of the high-Tc cuprates, which are in excellent agreement with the experimental data for single-layered materials such as LSCO, Bi2201 and Hg1201. Our effective Hamiltonian, defined in the oxygen square sub-lattices formed by the alternate hybridization of $p_x$ and $p_y$ orbitals with the $3d$ copper orbitals, provides an unified explanation for the $d_{x^2-y^2}$ symmetry of both the SC and PG order parameters. Attractive and repulsive interactions involve holes of the two different sublattices and can be derived from the spin-fermion model. Optimal doping occurs when the chemical potential vanishes. For $N$-layered cuprates, the growth of the optimal temperature with $N$, as well as the trend of the SC and AF domes to superimpose, can be simply understood. Our results for the optimal SC transition temperature are in excellent agreement with the experiments for $N=2$ materials of the $Bi$ and $Hg$ families. For $N=3$ the agreement is still satisfactory, while for $N>3$, it becomes poor. The explanation for these facts allows us to suggest a method for increasing the critical SC temperature in cuprates.