Using the density-functional perturbation theory with structural optimization, we investigate the electronic structure, phonon spectra, and superconductivity of 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 obtained T c ≃ 9.1 K is very close to its experimental value, indicating that it is a conventional electron-phonon superconductor.

It is shown that bilayer phosphorene can be transformed from a direct-gap semiconductor to a BCS superconductor by intercalating Li atoms. For the Li-intercalated bilayer phosphorene, we find that the electron occupation of Li-derived band is small and superconductivity is intrinsic. With increasing the intercalation of Li atoms, both increased metallicity and strong electron-phonon coupling are favorable for the enhancement of superconductivity. The obtained electron-phonon coupling λ can be larger than 1 and the superconducting temperature Tc can be increased up to 16.5 K, suggesting that phosphorene may be a good candidate for a nanoscale superconductor.