SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 51: Surface Magnetism

O 51.4: Vortrag

Mittwoch, 29. März 2023, 12:15–12:30, REC C 213

Electron Spin-Polarizing Mechanisms in Chiral CuO and CoO_x Catalyst Surfaces — •Paul Valerian Möllers¹, Jimeng Wei², Supriya Ghosh², Soma Salamon³, Manfred Bartsch¹, Heiko Wende³, David Waldeck², and Helmut Zacharias¹ — ¹Center for Soft Nanoscience, WWU Münster, Germany — ²Department of Chemistry, University of Pittsburgh, Pittsburgh, USA — ³Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), Universität Duisburg-Essen, Germany

Spin-polarized catalytic surfaces can greatly enhance the selectivity of chemical reactions, e.g., in a photoinduced water splitting process. Here, we present new insights into the mechanisms that give rise to the spin polarization in chiral cupric oxide¹ (CuO) and cobalt oxide² (CoO_x) layers deposited using a method pioneered by Switzer et al.³ Photoelectrons were excited with deep-UV laser pulses and their average spin polarization (SP) was measured. For CuO layers, the energy dependence of the spin polarization reveals that the measured SP values can be rationalized assuming an intrinsic SP in the chiral oxide layer and a chirality-induced spin selectivity (CISS)-related spin filtering of the electrons.⁴ On chiral CoO_x layers, the SP was found to depend on the Co oxidation state, which allows for reversible switching of the preferred spin orientation. The results support efforts towards a rational design of further spin-selective catalytic oxide materials. ¹K.B. Ghosh et al., J. Phys. Chem. C 123, 3024 (2019) ²S. Ghosh et al., J. Phys. Chem. C 124, 22610 (2020) ³Kothari et al., Chem. Mater. 16, 4232 (2004) ⁴Möllers et al., ACS Nano 16, 12145 (2022)