Regensburg 2025 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 11: Electronic Structure of Surfaces: Spectroscopy, Surface States I

O 11.10: Vortrag

Montag, 17. März 2025, 17:15–17:30, H4

Unoccupied electronic structure of the AgTe/Ag(111) surface alloy: A spin-resolved inverse photoemission study — •Marcel Holtmann, Carolin Benfer, and Markus Donath — Physikalisches Institut, Münster University, Germany

The AgTe/Ag(111) surface-alloy system has recently been investigated to understand the microscopic origin of the Rashba effect [1]. ARPES measurements suggest that tellurium p orbitals hybridize with states of the Ag(111) substrate resulting in two p_xy valence bands. For the unoccupied band structure, a third hybridization state with out-of-plane symmetry is detected using two-photon photoemission. Apart from this, the unoccupied electronic structure of AgTe/Ag(111) remains unexplored.
We employed spin- and angle-resolved inverse photoemission (IPE) to measure the unoccupied electronic structure with a broader scope. Using our rotatable spin-polarized electron source, we were able to measure the three-dimensional spin texture of the unoccupied states. As expected in [1], we found that the hybridization state shows a large Rashba-type spin splitting, which is untypical for non-heavy-metal systems. Using several photon detectors at different take-off angles to measure the angular distribution of the emitted photons, we gained access to the orbital symmetries of the involved electronic states. In addition, like the pristine Ag(111) surface, the AgTe/Ag(111) surface hosts an image-potential state.
[1] M. Ünzelmann et al., Phys. Rev. Lett. 124, 176401 (2020)

Keywords: Inverse Photoemission; Surface Alloy; OAM; Spin; Rashba