By exciting photoelectrons close to the threshold, photoemission experiments are very sensitive to differences in the work function. In this work an energetically tunable laser system has been used to show exemplarily for the BaTiO3(001) surface that this contrast mechanism enables the imaging of ferroelectric domains by using a photoemission electron microscope. There, the domain patterns observed at room and higher temperatures are analyzed. Also for the (001) surface of multiferroic BiFeO3 domains are observed, which additionally show linear dichroism. Very likely, this dichroic behavior is caused by the antiferromagnetic properties of the material. In Two-Photon-Photoemission experiments the electron dynamics of a Ag(001) surface using the examples of the first image potential state and plasmonic excitations were spatially resolved investigated with fs-time resolution. Furthermore, photoemission experiments of thin sexithiophene films lead to the conclusion that the exciting UV radiation may cause an oligomerisation of the organic molecules. |