Full-bandwidth Eliashberg theory of superconductivity beyond Migdal's approximation
نویسندگان
چکیده
منابع مشابه
FAILURE OF THE MIGDAL-ELIASHBERG THEORY OF SUPERCONDUCTIVITY IN Rb3C60
We discuss the compatibility of the most accurate experimental data with the ordinary Migdal-Eliashberg theory of superconductivity in the fullerene compound Rb3C60. By using different model phonon spectra we conclude that the experimental data can be fitted only by invoking an electron-phonon coupling of order λ ≃ 3. This exceedingly high value is unphysical and it is not consistent with the b...
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In this paper, through an exhaustive analysis within the Migdal-Eliashberg theory, we show the incompatibility of experimental data of Rb3C60 with the basic assumptions of the standard theory of su-perconductivity. For different models of the electron-phonon spectral function α 2 F (Ω) we solve numerically the Eliashberg equations to find which values of the electron-phonon coupling λ, of the l...
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Density-functional calculations of the phonon spectrum and electron-phonon coupling in MgB (2) are presented. The E(2g) phonons, which involve in-plane B displacements, couple strongly to the p(x,y) electronic bands. The isotropic electron-phonon coupling constant is calculated to be about 0.8. Allowing for different order parameters in different bands, the superconducting lambda in the clean l...
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ژورنال
عنوان ژورنال: Physical Review B
سال: 2020
ISSN: 2469-9950,2469-9969
DOI: 10.1103/physrevb.102.024503