Fig. 3: Eliashberg calculations for phonon-mediated superconductors in EPW.
From: Electron–phonon physics from first principles using the EPW code
a Band structure and DOS of 2H-NbSe2. b Phonon dispersion relations, phonon density of states (blue line), Eliashberg spectral function α2F (solid red line), and cumulative electron-phonon coupling strength λ (dashed red line) of 2H-NbSe2. In (a), the bands obtained by Wannier interpolation are shown in dashed red lines. c Momentum-resolved superconducting gap of 2H-NbSe2, color-coded on the Fermi surface220 and evaluated at 2 K [same dataset as in (d)]. d Energy distribution of the superconducting gap of 2H-NbSe2 as a function of temperature, calculated using the FBW Eliashberg approach, chemical potential set to the Fermi energy, and a Matsubara frequency cutoff of 0.4 eV. The energy window is 0.4 eV for the black line, and 0.8 eV for the red line. e Gap function of 2H-NbSe2 obtained from the FBW approach using fixed chemical potential (black line) and variable chemical potential (blue line). The energy window and Matsubara cutoff are both 0.4 eV. f Same as in (e), but using a Matsubara cutoff of 1.2 eV. g Comparison between the gap functions obtained with the FBW approach (black line) and the FSR approach (blue). Both the energy window and the Matsubara cutoff are 0.4 eV. h Same as in (g), but using a sparse Matsubara frequency grid. The dashed lines in d–h represent averages of the gap distributions.
