Temperature vs. doping phase diagram of cuprate superconductors

TL;DR

This paper models the phase diagram of cuprate superconductors using a spin-fermion approach, predicting a quantum critical point and explaining the doping-dependent superconducting dome with a calculated critical temperature close to experimental values.

Contribution

It introduces a spin-fermion model that predicts a quantum critical point and reproduces the doping-dependent superconducting dome without free parameters.

Findings

Identifies a quantum critical point for superconducting interaction.

Reproduces the dome-shaped T_c dependence on doping.

Calculates T_c at optimal doping as approximately 45 K.

Abstract

Starting from a spin-fermion model for the cuprate superconductors, we obtain an effective interaction for the charge carriers by integrating out the spin degrees of freedom. Our model predicts a quantum critical point for the superconducting interaction coupling, which sets up a threshold for the onset of superconductivity in the system. We show that the physical value of this coupling is below this threshold, thus explaining why there is no superconducting phase for the undoped system. Then, by including doping, we find a dome-shaped dependence of the critical temperature as charge carriers are added to the system, in agreement with the experimental phase diagram. The superconducting critical temperature is calculated without adjusting any free parameter and yields, at optimal doping $ T_c \sim $ 45 K, which is comparable to the experimental data.