Phonon spectra and superconductivity of the BiS 2 -based compounds LaO 1−x F x BiS 2

Using the density-functional perturbation theory with structural optimization, we investigate the electronic structure, phonon spectra, and superconductivity of the BiS 2 -based layered compounds LaO 1− x F x BiS 2 . For LaO 0.5 F 0.5 BiS 2 , the calculated electron-phonon coupling constant is equal to λ = 0.8, and the obtained T c ≃ 9.1 K is very close to its experimental value, indicating that it is a conventional electron-phonon superconductor.