Influence of interband interaction on Isotope Effect Exponent of MgB2 Superconductors

TL;DR

This paper derives a formula for the critical temperature and isotope effect exponent in two-band superconductors like MgB2, highlighting the significant influence of interband electron-phonon interactions on isotope effects.

Contribution

It introduces a new theoretical model considering interband interactions and non-phonon effects to explain isotope effects in MgB2 superconductors.

Findings

Isotope effect exponent of MgB2 is approximately 0.3 at 40 K.

Interband electron-phonon interactions significantly influence the isotope effect.

The model applies in the weak-coupling limit for two-band superconductors.

Abstract

The exact formula of Tc's equation and the isotope effect exponent of two-band s-wave superconductors in weak-coupling limit are derived by considering the influence of interband interaction. The paring interaction in each band consisted of 2 parts : the electron-phonon interaction and non-phonon interaction are included in our model. The isotope effect exponent of MgB2 equal to 0.3 with Tc 40 K can be found in the weak coupling regime and interband interaction of electron-phonon interaction show more effect on isotope effect exponent than of non-phonon interaction.