Electronic Structure of Ru(0001)

For a long time Ruthenium has attracted considerable interest due to its applications in catalytic processes. These days a renewed interest in this surface derives from its current use as substrate to grow graphene by low pressure CVD. In this work we used k-resolved inverse photoemission spectroscopy (KRIPES) and an Ab initio calculations of the electronic structure of Ru(0001), to determine the energy dispersion of the different states and surface resonances. The setup to perform KRIPES measurements mainly consists of an electron gun capable of producing a parallel electron beam with energies up to 30 eV and a Geiger Müller counter filled with iodine as discharge gas capped with a SrF2 window.This configuration allows the detection of optical transitions between unoccupied bands (photons of 9.5 ±0.2 eV). The comparison between IPES features and calculations enabled us to identify several Ru bulk states and surface resonances in the ΓΜΓ direction up to 8 eV above the Fermi Energy.