Probing multiband superconductivity by point-contact spectroscopy

TL;DR

This paper reviews how point-contact spectroscopy can be used to investigate the properties of superconductors, especially multiband and anisotropic types, by analyzing the energy gap and its symmetry.

Contribution

It provides a comprehensive review of experimental and theoretical methods of point-contact spectroscopy applied to complex superconductors.

Findings

Effective in probing multiband superconductivity

Reveals information on energy gap amplitude and symmetry

Applicable to anisotropic superconductors

Abstract

Point-contact spectroscopy was originally developed for the determination of the electron-phonon spectral function in normal metals. However, in the past 20 years it has become an important tool in the investigation of superconductors. As a matter of fact, point contacts between a normal metal and a superconductor can provide information on the amplitude and symmetry of the energy gap that, in the superconducting state, opens up at the Fermi level. In this paper we review the experimental and theoretical aspects of point-contact spectroscopy in superconductors, and we give an experimental survey of the most recent applications of this technique to anisotropic and multiband superconductors.