Excited electron dynamics in Cu nanowires supported on a Cu(111) surface

We present a theoretical study of the excited electron dynamics in infinite Cu monoatomic chains (nanowires) supported on a Cu(111) surface. A joint approach based on the wave packet propagation and the density functional theory is used. The nanowire-induced potential obtained from ab initio density functional theory calculations serves as an input for the wave-packet propagation study of the excited electron dynamics. The energy dispersion and the lifetime of an unoccupied one-dimensional (1D) nanowire-localized electronic band with sp character are obtained. From the group velocity and lifetime of the 1D sp-band states, it follows that an excited electron can travel about four to five atomic sites along the nanowire before its escape into the bulk. We show that the surface projected band gap and the surface Brillouin zone backfolding of the substrate states play a fundamental role in the lifetime of the nanowire-localized states.