Electron-phonon interaction in the f-band metals La, Ce and Th: Electronic aspects including the spin-orbit interactions

Abstract

The electron-ion scattering parameter η is calculated for the f-band metals La, Ce and Th using self-consistent muffin-tin potentials. The corrections within the rigid muffin-tin approximation (RMTA) due to spin-orbit coupling derived by John and Hamann are found to increase η by 1% in La and 4% in Th, and by 10% and 33% in the α and γ phases of Ce, respectively. The RMTA expression is reinterpreted to provide an understanding of the low values of η in Ce (0.7 to 1.1 eV/Å 2) in spite of an extremely large density of states at the Fermi level. Using moments of the measured phonon spectra, the superconducting transition temperature is calculated and compared with experiment. The RMTA appears to overestimate η by approximately 25% in these metals, although spin fluctuations may be contributing to this apparent discrepancy with experiment.