Anisotropy effects of the gap function on superconducting properties in a 2H-type transition-metal dichalcogenide NbS2 are studied by solving the anisotropic Eliashberg equation with the use of Fermi-surface harmonics. Due to the characteristic dependences on wave vectors of the electron-phonon interaction and renornialized phonon frequencies, anisotropic components of the electron phonon spectral function have relatively large values in the frequency range between 5 and 10 meV, where the frequencies of the ∑1-phonon modes around q -2/3ΓM are renormalized significantly. The superconducting transition temperature Tc evaluated by solving the anisotropic Eliashberg equation is slightly higher than that evaluated by solving the isotropic Eliashberg equation. Anisotropy of the mass enhancement factor and that of the superconducting gap function just below Tc are also evaluated.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering