Antiferromagnetic phase diagram of the cuprate superconductors

TL;DR

This paper models the antiferromagnetic phase diagram of cuprate superconductors using a spin-fermion approach, successfully matching experimental data and unifying the behavior of hole- and electron-doped compounds.

Contribution

It introduces an effective nonlinear sigma-field Hamiltonian derived from the spin-fermion model that accounts for doping effects in cuprates.

Findings

Accurately reproduces the antiferromagnetic phase diagram of YBa2Cu3O6+x.

Provides a unified description for hole- and electron-doped cuprates.

Shows the suppression of antiferromagnetism with increasing chemical potential.

Abstract

Taking the spin-fermion model as the starting point for describing the cuprate superconductors, we obtain an effective nonlinear sigma-field hamiltonian, which takes into account the effect of doping in the system. We obtain an expression for the spin-wave velocity as a function of the chemical potential. For appropriate values of the parameters we determine the antiferromagnetic phase diagram for the YBa$_2$Cu$_3$O$_{6+x}$ compound as a function of the dopant concentration in good agreement with the experimental data. Furthermore, our approach provides a unified description for the phase diagrams of the hole-doped and the electron doped compounds, which is consistent with the remarkable similarity between the phase diagrams of these compounds, since we have obtained the suppression of the antiferromagnetic phase as the modulus of the chemical potential increases. The aforementioned result then follows by considering positive values of the chemical potential related to the addition of holes to the system, while negative values correspond to the addition of electrons.