8. Electronic excitations in low-dimensional nanostructures

(S. Gao, B. Hellsing, T. Petersson)

First principles electron structure approach will be applied to investigate the dynamical response of (i) thin films, ranging from a single atomic layer to multi-layers, and (ii) adsorbed metal clusters, ranging from nano meter size quantum dots to micrometer sized islands. We have an established collaboration with experimental activity at the Department of Applied Physics at Chalmers and Institute of Physics, Chinese Academy of Sciences. So far we have determined plasmon frequencies and decay mechanisms for transition metal films. Recent photoemission data suggest possibles contributions from collective plasmon excitations in single alkali metal over-layers. We are aiming at a more accurate description of ultra thin films and quantum dots by including the atomic structure, which so far has been left out in a jellium model. Recent studies show that the plasmon excitation energies change significantly when the jellium model is replaced by atomic pseudo-potentials. Advanced theoretical tools such as time dependent local density approximation (TDLDA) is in use and will be developed further. The project is well suited for a new PhD student. The field of nano-plasmonics is one of the most rapidly growing fields of solid state physics today. The project will strengthen the collaboration theorists-experimentalists and between physics of GU and Chalmers within the framework of “Fysikcentrum i Göteborg”. ”.