Effective mass enhancement and ultrafast electron dynamics of Au(111) surface state coupled to a quantum well

The authors investigate the band dispersion and electron dynamics of the surface state of a gold quantum cavity grown on a tungsten substrate. They find a kink structure above the Fermi level that is consistent with a remarkable renormalization of the effective mass and electron relaxation times significantly slower than expected for a bulk metallic system. Their results demonstrate how the interplay between quantum confinement in the gold film and the electronic structure of the substrate determine the equilibrium and dynamical properties of the surface state