Phonons and electron-phonon interaction at the Sb(111) surface

The bulk and surface dynamics of Sb(111) and the corresponding electron-phonon interaction have been calculated by density functional perturbation theory. The surface phonon bands reveal features related to a remarkable stiffening of the surface bilayer with respect to the bulk ones. The main contribution to electron-phonon interaction involves transitions between surface and bulk states, mostly driven by bulk phonons, and is found to be in good agreement with the value derived from spin angle-resolved photoemission spectroscopy.