Regensburg 2025 – scientific programme
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O: Fachverband Oberflächenphysik
O 32: Heterogeneous Catalysis I
O 32.2: Talk
Tuesday, March 18, 2025, 10:45–11:00, H25
Structural and chemical analysis of coexisting hexagoal and monoclinic phases of samarium oxide on Cu(111) — •Björn Riedel, lars Buss, Raquel Sanchez-Barquilla, and Jan Ingo Flege — Applied Physics and Semiconductor Spectroscopy, Brandenburg University of Technology Cottbus-Senftenberg, Germany
The absence of in-depth spectroscopic and structural studies on model systems leads to a knowledge gap in understanding how the structure of samaria influences its chemical behavior. A multi-method approach has been employed to investigate the Cu(111)-supported Sm2O3 surface with high structural and chemical sensitivity by using low-energy electron microscopy (LEEM) in combination with X-ray absorption photoemission electron microscopy (XAS-PEEM) and other complementary methods such as micro-spot low-energy electron diffraction (µLEED) and X-ray photoelectron spectroscopy (XPS). Our measurements show the phase coexistence of small hexagonal A-Sm2O3(0001) islands and monoclinic B-Sm2O3(100) rectangular-shaped islands with different rotated rectangular domains. Furthermore, the redox properties of both Sm2O3 phases were studied by exposing the system to reducing (H2) and oxidizing (CO2) conditions, indicating a face-dependent reduction and oxidation behavior. Moreover, the monoclinic Sm2O3(100) islands appear less stable as they change to the hexagonal phase during annealing. These results indicate a highly dynamic system that can easily be adjusted by adapting the growth conditions, such as growth temperature and oxygen partial pressure.
Keywords: Samaria; LEEM; XAS-PEEM; structure sensitivity