Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 82: Electronic Structure of Surfaces 2
O 82.3: Vortrag
Freitag, 9. September 2022, 11:00–11:15, S053
Spin-polarized VLEED from Au(111): Surface sensitivity of the scattering process — •Christoph Angrick1, Jürgen Braun2, and Markus Donath1 — 1Westfälische Wilhelms-Universität Münster — 2Ludwig-Maximilians Universität München
Low-energy electron diffraction from Au(111) shows the well-known threefold symmetry of the diffracted electron beams despite the sixfold symmetry of the surface layer. This is due to the influence of the second and deeper layers and the probing depth of the electrons. In this work, we investigated Au(111) with spin-polarized very-low-energy electron diffraction (VLEED) [1,2] experimentally and theoretically. We monitor the reflected specular beam at a fixed polar angle of incidence of Θ=45∘ while the azimuthal orientation of the crystal is varied. This puts the surface sensitivity of the VLEED scattering process to a test.
Our results show that the electron reflection and the spin-orbit-induced reflection asymmetry along Γ M and Γ M′ are equivalent. The observed sixfold symmetry suggests a sensitivity to one atomic layer only. At azimuth angles deviating from the high-symmetry directions Γ M and Γ M′, however, the VLEED signal from Au(111) shows a threefold symmetry. To reveal the origin of this effect, we varied the parameters in the calculation. The results indicate a non-negligible influence of the second atomic layer in the VLEED scattering process.
[1] Burgbacher et al., Phys. Rev. B 87, 195411 (2013)
[2] Angrick et al., J. Phys.: Condens. Matter 33, 115001 (2020)