Recent Advances In 2D-Band Structure Imaging By k-PEEM and Prospects For Technological Materials

摘要

The imaging of surfaces using the PhotoElectron Emission Microscopy (PEEM) technique has recently received considerable interest, mainly thanks to the use of high brilliance synchrotron radiation which facilitates the study of surface properties and chemical selectivity. By inserting a transfer lens in the optical column of a high transmission and full energy-filtering PEEM, it is possible to image the back focal plane, named k-PEEM imaging mode. Hence, the corresponding image shows the angular distribution of the emitted photoelectrons for a given kinetic energy. By varying the kinetic energy, the complete energy filtering provides full 2D cuts of the band structure in reciprocal space. In this paper, we present the principles and the capabilities of this new imaging mode, and compare it to the standard ARPES technique. Then, we present results obtained on a model sample: Ag(100), and on a technological sample, epitaxial graphene on SiC(0001), highlighting the potential of this new imaging mode for the spatially resolved characterization of the electronic structure of monocrystalline materials in devices.