Superconductivity in simple elemental solids - A computational study of boron-doped diamond and high pressure phases of Li and Si

Abstract

The superconducting phase of several elemental solids under ambient (p-doped diamond) and high pressure conditions (face-centred cubic phases of Li and Si-V) have been studied with the linear response method. The computed superconducting temperatures, based on the weak coupling Bardeen-Cooper-Schrieffer theory, are found to be in good agreement with experiments. Analysis of the electronic structure and phonon band structures shows that changes in the chemical bonding are responsible for the strong electron-phonon coupling. In boron-doped diamond, the Jahn-Teller effect is shown to be the dominant factor. For high pressure FCC Li and Si-V, rehybridization has led to the redistribution of valence electrons into the interstitial space and weakened the covalent interactions that helped to enhance the electron-phonon coupling.