Calculating a local oscillating quasiparticle’s lifetime at screened defects in solids

We report on a novel approach to calculate quasiparticle lifetimes of localized initial states, which decay into the continuum of underlying quasi-free quasiparticle states in the vicinity of point defects and steps in solids. By using this interpretation of the inelastic damping of wavefunctions, the lifetime becomes a local property. In particular, we consider electrons, which are injected by a scanning tunneling microscope tip into the surface state of a noble metal surface. We investigate numerically the configuration of a single scatterer, a chain of scatterers, and a triangular quantum corral. As compared to an exponential increase of the damping from prior theories, we find an oscillating damping together with a linear background of the resulting measurement signal. The different configurations show increased lifetimes with increasing dimensionality as their scattering phase space is decreased.