Thermal properties of MgB2: the effect of disorder on gap amplitudes and relaxation times of π and σ bands

Description

We present thermal conductivity and specific heat measurements on MgB2 and Mg-AlB2 samples. Thermal properties have been analyzed by using a two-gap model in order to estimate the gap amplitudes, Delta(0)(pi) and Delta(0)(sigma) and the intra-band scattering rates, Gamma(sigmasigma) and Gamma(pipi). Delta(0)(sigma) rapidly decreases as a function of Al doping and disorder, while Delta(0)(pi) is rather constant. Gamma(sigmasigma) and Gamma(pipi) are increased by disorder, being Gamma(pipi) more affected than Gamma(sigmasigma).

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