Signatures of interband scattering in spectroscopic experiments on $MgB_2$

TL;DR

This paper uses a two-band strong coupling model to analyze spectroscopic data on MgB2, revealing how interband scattering influences features in tunneling, Raman, and optical conductivity measurements.

Contribution

It introduces a comprehensive analysis of interband scattering effects in MgB2 using a two-band strong coupling framework, explaining experimental features across multiple spectroscopic techniques.

Findings

Interband scattering explains features at 8-10 meV in tunneling and Raman spectra.

Strong coupling effects are crucial for matching optical conductivity data.

Predicted interband scattering signatures in optical spectra.

Abstract

Within a two-band, strong coupling model we analyze SIS-tunneling conductance, Raman scattering and optical conductivity measured on $MgB_2$ samples. We find that features observed in tunneling and Raman spectroscopy at intermediate energies $\omega=\Delta_{\sigma}+\Delta_{\pi}\simeq 8\div 10meV$ can be consistently explained when incoherent scattering between $\sigma$ and $\pi$ band is considered. We calculate the optical conductivity and find that strong coupling effects are important for explaining the presently available data, and predict the location and magnitude of interband scattering features for this spectroscopic probe as well.