Electron-phonon pairing mechanism: cuprates with high value of the critical temperature

TL;DR

This paper tests a modified electron-phonon pairing model for high-temperature cuprate superconductors, successfully predicting the doping dependence of the energy gap to critical temperature ratio in several compounds.

Contribution

It introduces a theoretical framework that accurately predicts the doping dependence of the energy gap ratio in high-Tc cuprates, supporting the electron-phonon pairing mechanism.

Findings

The model predicts the ratio R1 as a function of doping p.

Numerical results match experimental data for various cuprates.

A formula describing R1(p) is provided.

Abstract

The model for the cuprates based on the modified electron-phonon pairing mechanism has been tested. For this purpose, the superconductors with high value of the critical temperature have been taken into consideration. In particular: ${\rm YBa_{2}Cu_{3}O_{7-y}}$, ${\rm HgBa_{2}CuO_{4+y}}$, ${\rm HgBa_{2}Cu_{1-x}Zn_{x}O_{4+y}}$, and ${\rm HgBa_{2}Ca_{2}Cu_{3}O_{8+y}}$. It has been shown that the dependence of the ratio $R_{1}\equiv 2\Delta_{tot}^{(0)}/k_{B}T_{C}$ on the doping ($p$) can be properly predicted in the framework of the presented theory; the symbol $\Delta_{tot}^{(0)}$ denotes the energy gap amplitude at the temperature of zero Kelvin, and $T_{C}$ is the critical temperature. The numerical results have been supplemented by the formula which describes the function $R_{1}(p)$.