Point-contact spectroscopy of two-band superconductor MgB2

TL;DR

This paper reviews point-contact spectroscopy studies on MgB2, revealing how superconducting gaps vary with temperature and magnetic field, and correlating these with phonon interactions, while also comparing with other diborides.

Contribution

It provides a comprehensive analysis of the superconducting gaps and electron-phonon interactions in MgB2 using PCS, highlighting the correlation with boron vibrations and comparing with other diborides.

Findings

Superconducting gap varies with temperature and magnetic field.

Correlation between gap value and boron vibration mode.

Comparison of PCS data with nonsuperconducting diborides.

Abstract

The progress in investigation of two-band superconductor MgB$_2$ by the point-contact spectroscopy (PCS) is given. Results of study of superconducting gap temperature and magnetic field dependence for two-dimensional $\sigma$ and three-dimensional $\pi$ band and electron-phonon-interaction spectral function are presented. Correlation between the gap value and the intensity of the high T$_c$ driving force -- $E_{2g}$ boron vibration mode, is provided. PCS data on some nonsuperconducting transition metal diborides are surveyed for comparison.