UP or DOWN? Rashba-type spin structures in sp- and d-derived surface states below and beyond the Fermi level
Prof. Dr. Markus Donath (Westfälische Wilhelms-Universität)

Rashba‐type spin splittings in the surface electronic structure of heavy elements and topological insulators are a hot topic of today’s research in condensed matter physics. The interest is guided by possible applications of these materials in spintronic devices, in which the electron spin is used as an information carrier.
In this talk, I will present several experimental studies on surface states of different origin and with distinct spin configurations. An sp‐derived surface state at Au(111) was the starting point for the study of Rashba‐type spin splittings. Inverse‐photoemission data show the state above the Fermi level and, thus, complement existing photoemission data for the occupied part. At W(110), a spinpolarized Dirac‐cone‐like surface state with d character was identified, which appears below the Fermi level in a spin‐orbit‐induced symmetry gap of the projected bulk‐band structure. At Tl/Si(111), an unoccupied surface state with a spin‐dependent energy splitting of more the 0.5 eV exhibits a distinct spin structure around the K point, leading to almost complete spin polarization at the Fermi level. Making combined use of direct and inverse photoemission with spin resolution, we were able to characterize the electronic states and their spin structure below and beyond the Fermi level.
All interested are cordially welcome! Organize your personal meeting with the lecturer by contacting H.-J. Elmers