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The determination of the electron-phonon interaction from tunneling data in the two-band superconductor MgB2

D. Daghero·R. S. Gonnelli·G. A. Ummarino·O. V. Dolgov·J. Kortus·A. A. Golubov·S. V. Shulga
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Abstract

We calculate the tunneling density of states (DOS) of MgB2 for different tunneling directions, by directly solving the real-axis, two-band Eliashberg equations (EE). Then we show that the numeric inversion of the standard single-band EE, if applied to the DOS of the two-band superconductor MgB2, may lead to wrong estimates of the strength of certain phonon branches (e.g. the E_2g) in the extracted electron-phonon spectral function alpha^(2)F(omega). The fine structures produced by the two-band interaction turn out to be clearly observable only for tunneling along the ab planes in high-quality single crystals. The results are compared to recent experimental data.

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D. Daghero, R. S. Gonnelli, G. A. Ummarino, O. V. Dolgov, J. Kortus, A. A. Golubov, S. V. Shulga. 2003-05-23. The determination of the electron-phonon interaction from tunneling data in the two-band superconductor MgB2. https://doi.org/10.1016/j.physc.2004.02.098

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