Pressure dependence of critical temperature in MgB2 and two bands Eliashberg theory

TL;DR

This study models how pressure affects the critical temperature of MgB2 superconductors using two-band Eliashberg theory, fitting experimental data and predicting gap variations.

Contribution

It applies two-band Eliashberg theory with first-principles calculations to accurately model pressure effects on Tc in MgB2, providing new insights into electron-phonon interactions.

Findings

Excellent fit to experimental Tc vs. pressure data

Predicted pressure dependence of superconducting gaps

Insights into electron-phonon interaction variation with pressure

Abstract

The variation of the superconducting critical temperature Tc as a function of the pressure p in the magnesium diboride MgB2 has been studied in the framework of two-bands Eliashberg theory and traditional phonon coupling mechanism. I have solved the two-bands Eliashberg equations using first-principle calculations or simple assumptions for the variation, with the pressure, of the relevant physical quantities. I have found that the experimental Tc versus p curve can be fitted very well and information can be obtained on the dependence of the electron-phonon interaction matrix <I^{2}> by pressure. The pressure dependence of the superconductive gaps Delta{sigma} and Delta{pi} is also predicted.