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Specific heat of MgB$_2$ in a one- and a two-band model from first-principles calculations

A. A. Golubov·J. Kortus·O. V. Dolgov·O. Jepsen·Y. Kong·O. K. Andersen·B. J. Gibson·K. Ahn·R. K. Kremer
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Abstract

The heat capacity anomaly at the transition to superconductivity of the layered superconductor MgB$_2$ is compared to first-principles calculations with the Coulomb repulsion, $μ^\ast$, as the only parameter which is fixed to give the measured $T_c$. We solve the Eliashberg equations for both an isotropic one-band and a two-band model with different superconducting gaps on the $π$ and $σ$ Fermi surfaces. The agreement with experiments is considerably better for the two-band model than for the one-band model.

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A. A. Golubov, J. Kortus, O. V. Dolgov, O. Jepsen, Y. Kong, O. K. Andersen, B. J. Gibson, K. Ahn, R. K. Kremer. 2002-01-31. Specific heat of MgB$_2$ in a one- and a two-band model from first-principles calculations. https://doi.org/10.1088/0953-8984%2F14%2F6%2F320

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