Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 26: Surface Magnetism
O 26.8: Vortrag
Dienstag, 6. September 2022, 12:15–12:30, H4
Chirality-induced electron spin polarization in chiral CuO and CoOx 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, 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 confirm that spin-polarized (photo)currents can be obtained from chiral cupric oxide1 (CuO) and cobalt oxide2 (CoOx), and explore the underlying mechanism. Chiral oxide thin films were 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 thin films, correlating the SP values with electron energy spectra 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. On chiral CoOx 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.
1 J. Phys. Chem. C 123, 3024 (2019) 2 J. Phys. Chem. C 124, 22610 (2020) 3 Chem. Mater. 16, 4232 (2004)