Ab initio investigations of the phonon anomaly and superconductivity in fcc La

Abstract

We have employed the ab initio plane wave pseudopotential method within a generalized gradient approximation of the density functional theory and a linear response approach to investigate the phonon anomaly and superconductivity in fcc La. Our results confirm the presence of the experimentally observed softening behavior of the transverse acoustic branch along the [111] direction for both zero pressure. This behavior is found to be present even at a pressure of 50 kbar. With a reasonable choice of 0.1 for the Coulomb pseudopotential mu*, our estimate of the superconducting critical temperature of 6.44 K at zero pressure is in good agreement with the experimental value of 6.0 K. Our work further suggests that at 50 kbar the critical temperature will increase to 9.26 K. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.2981192]