Momentum-dependent ultrafast dynamics of image states on flat and stepped Cu(111) surfaces

Summary form only given. Ultrafast time-resolved two-photon photoemission has recently been used to probe carrier dynamics at surfaces and interfaces. Here we describe a k-space state-resolved study of image-state lifetimes, which measures the time evolution of the photoexcited electron population at different points in the momentum space. Image electrons are weakly bound surface electrons with very narrow spectral features. Studies are done on both stepped and flat surfaces in order to understand image electron interactions with a step potential. The results suggest a new relaxation channel for image-state electrons on stepped surfaces.