Thermal properties of MgB2: the effect of disorder on gap amplitudes and relaxation times of p and s bands

TL;DR

This study investigates how disorder and aluminum doping affect the thermal conductivity, specific heat, and superconducting gap amplitudes in MgB2, revealing that disorder significantly reduces the smaller gap and increases intra-band scattering rates.

Contribution

It provides new insights into the impact of disorder on the two-gap superconductivity and intra-band scattering in MgB2 through detailed thermal measurements and modeling.

Findings

D(0)s decreases rapidly with Al doping and disorder

D(0)p remains relatively constant despite doping and disorder

Intra-band scattering rates Gss and Gpp increase with disorder, Gpp more significantly

Abstract

We present thermal conductivity and specific heat measurements on MgB2 and Mg-AlB2 samples. Thermal properties have been analysed by using a two-gap model in order to estimate the gap amplitudes, D(0)p and D(0)s and the intra-band scattering rates, Gss and Gpp. As a function of Al doping and disorder D(0)s rapidly decreases, while D(0)p is rather constant. Gss and Gpp are increased by the disorder, being Gpp more affected than Gss.