From the spin-fermion model to anisotropic superconductivity

TL;DR

This paper employs the spin-fermion model to analyze high-temperature superconductivity in cuprates, demonstrating how spin fluctuations induce anisotropic pairing and calculating critical temperatures consistent with experimental data.

Contribution

It introduces a large wavelength approach to connect spin fluctuations with anisotropic superconducting gaps in cuprates.

Findings

Superconducting gap symmetry is determined by anisotropic Kondo interactions.

Calculated Tc values match experimental trends across hole concentrations.

Ferromagnetic spin fluctuations couple to oxygen holes to induce pairing.

Abstract

We use the spin-fermion model to describe the CuO$_2$ planes of the high-Tc superconductors. Using a large wavelength approach, we show that the ferromagnetic component of the Cu spin fluctuations couple to the oxygen holes producing a pairing interaction that leads to a superconducting gap whose symmetry is determined by the anisotropy of the Kondo interaction. We calculate Tc as a function of the hole concentration in a mean-field approximation and our numerical results are in good agreement with the experiments.