Effects of pressure on the superconducting properties of magnesium diboride

TL;DR

This paper investigates how hydrostatic pressure influences the superconducting properties of MgB₂ using Eliashberg theory, aligning calculations with experimental data and predicting various physical parameters under pressure.

Contribution

It provides a comprehensive theoretical analysis of pressure effects on MgB₂'s superconducting properties, including predictions of multiple parameters and confirmation of electron-phonon coupling as the mechanism.

Findings

Pressure derivative of T_c matches experimental data

Predicted variations of energy gap and critical magnetic field under pressure

MgB₂ confirmed as an electron-phonon mediated superconductor

Abstract

We discuss the effects of hydrostatic pressure on the superconducting properties of MgB$_{2}$ within the framework of Eliashberg theory. By considering the pressure dependences of all parameters appearing in the McMillan formula, we show that the calculated pressure derivative of $T_{c}$ as well as the variation of $T_{c}$ with pressure are in good agreement with recent measurements. The pressure dependences of the energy gap $\Delta_{0}$, the effective interaction strength $N(E_{F})v$, the critical magnetic field $H_{c}(0)$, and the electronic specific heat coefficient $\gamma$ are also predicted for this system. A comparison of pressure effect in non-transition elements clearly suggests that MgB$_{2}$ is an electron-phonon mediated superconductor.