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arXiv · 0801.3197

Two-band parallel conductivity at terahertz frequencies in the superconducting state of MgB$_2$.

M. Ortolani·P. Dore·D. Di Castro·A. Perucchi·S. Lupi·V. Ferrando·M. Putti·I. Pallecchi·C. Ferdeghini·X. X. Xi
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Abstract

The optical response of the two-band superconductor MgB$_2$ has been studied in the 0.7-4 THz range on films with very low impurity level. The effect of the high-energy $σ$-gap is observed in the ratio $R_S/R_N$ between the normal and superconducting state reflectance, while in a neutron irradiated film with a slightly higher impurity level mainly the effect of the $π$-gap is evident as reported in previous experiments. At terahertz frequencies, the electrodynamic of MgB$_2$ can be well described by the two-band parallel conductivity model and is dominated by the $π$-bands when the impurity level is only slightly higher than that of an ultra-clean sample.

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M. Ortolani, P. Dore, D. Di Castro, A. Perucchi, S. Lupi, V. Ferrando, M. Putti, I. Pallecchi, C. Ferdeghini, X. X. Xi. 2008-01-21. Two-band parallel conductivity at terahertz frequencies in the superconducting state of MgB$_2$.. https://doi.org/10.1103/physrevb.77.100507

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