Linear-response studies of the electron-phonon interaction in metals

Applications of the first-principles linear-response method for calculating electron-phonon coupling parameters are presented. Calculations show that the electron-phonon coupling in the low-temperature 9R phase of Li is significantly weaker than in the room-temperature b.c.c. phase, which helps explain the observed absence of a superconducting transition down to the mK regime. Results for the electron-phonon interaction in compressed S indicate that the surprisingly high superconducting Tc of 17 K observed at 160 GPa arises from a combination of a moderately large electron-phonon mass enhancement parameter and a very high phonon energy scale for the compressed lattice. (orig.)