A first-principles study of electron–phonon coupling in electron-doped LiH

Abstract

The electronic structure, lattice dynamics, and electron–phonon coupling (EPC) of electron(n)-doped LiH have been extensively studied using ab initio methods within the virtualcrystal approximation. The overall agreement of the lattice constants and bulk modulus forpure LiH with the experiments is excellent if the zero-point motion is taken into account.From the theoretical calculation for n-doped LiH, it is indicated that metallicn-doped LiH might be a good superconductor. Moreover, the EPC parameterλ for n-doped LiH was found to increase with the dopant concentration,resulting from the softening of optical phonon modes and the increase of theelectron density of states at the Fermi level, while a decreasing trend ofλ was predicted for the presence of pressure. Phonon linewidth calculations suggested thatthe optical phonon mode makes the main contribution to the EPC. A possiblemechanism for the predicted superconductivity of n-doped LiH has been discussed.