MANIFESTATION OF ELECTRON-PHONON INTERACTION IN PHONON ANOMALY, SUPERCONDUCTIVITY AND TRANSPORT-PROPERTIES OF LAYERED 2H-NBS2

Role of electron-phonon interaction in physical properties of 2H-NbS2 is elucidated microscopically. Characteristic mode and wave vector dep endences of the electron-phonon interaction cause remarkable frequency renormalization of the Sigma(1) phonon modes around q = 2/3 Gamma M, which consist mainly of the Nb vibrations. The superconducting and the transport spectral functions have significant values only in the low- frequency range (omega < 20 meV) corresponding to the Nb vibrations. T he superconducting transition temperature and the tunneling spectra ar e obtained by solving the Eliashberg equation. The electrical and ther mal resistivities calculated by solving the Boltzmann equation with th e use of the transport spectral function agree with observations.