TY - GEN A1 - Pożarowska, Emilia A1 - Pleines, Linus A1 - Ewert, Moritz A1 - Prieto, Mauricio J. A1 - Tănase, Liviu Christian A1 - Souza Caldas, Lucas de A1 - Tiwari, Aarti A1 - Schmidt, Thomas A1 - Falta, Jens A1 - Krasovskii, Eugene A1 - Morales, Carlos A1 - Flege, Jan Ingo T1 - Preparation and stability of the hexagonal phase of samarium oxide on Ru(0001) T2 - Ultramicroscopy N2 - We have used low-energy electron microscopy (LEEM), micro-illumination low-energy electron diffraction (µLEED) supported by ab initio calculations, and X-ray absorption spectroscopy (XAS) to investigate in-situ and in real-time the structural properties of Sm2O3 deposits grown on Ru(0001), a rare-earth metal oxide model catalyst. Our results show that samarium oxide grows in a hexagonal A-Sm2O3 phase on Ru(0001), exhibiting a (0001) oriented-top facet and (113) side facets. Upon annealing, a structural transition from the hexagonal to cubic phase occurs, in which the Sm cations exhibit the +3 oxidation state. The unexpected initial growth in the A-Sm2O3 hexagonal phase and its gradual transition to a mixture with cubic C-Sm2O3 showcases the complexity of the system and the critical role of the substrate in the stabilization of the hexagonal phase, which was previously reported only at high pressures and temperatures for bulk samaria. Besides, these results highlight the potential interactions that Sm could have with other catalytic compounds with respect to the here gathered insights on the preparation conditions and the specific compounds with which it interacts. KW - Samarium oxide (Sm2O3) KW - low-energy electron microscopy (LEEM) KW - X-ray photoemission electron microscopy (XPEEM) KW - Facets KW - Epitaxy KW - Hexagonal phase Y1 - 2023 U6 - https://doi.org/10.1016/j.ultramic.2023.113755 SN - 0304-3991 SN - 1879-2723 VL - 250 ER - TY - GEN A1 - Hall, Braeden A1 - Schmidt, Kathleen A1 - Wagge, Jordan A1 - Lewis, Savannah C. A1 - Weissgerber, Sophia C. A1 - Kiunke, Felix A1 - Pfuhl, Gerit A1 - Stieger, Stefan A1 - Tran, Ulrich S. A1 - Barzykowski, Krystian A1 - Bogatyreva, Natalia A1 - Kowal, Marta A1 - Massar, KarlIJn A1 - Pernerstofer, Felizitas A1 - Sorokowski, Piotr A1 - Voracek, Martin A1 - Chartier, Christopher R. A1 - Brandt, Mark J. A1 - Grahe, Jon E. A1 - Özdoğru, Asil A. A1 - Andreychik, Michael R. A1 - Chen, Sau-Chin A1 - Evans, Thomas R. A1 - Hautekiet, Caro A1 - IJzerman, Hans A1 - Kačmár, Pavol A1 - Krafnick, Anthony J. A1 - Musser, Erica D. A1 - Vergauwe, Evie A1 - Werner, Kaitlyn M. A1 - Aczel, Balazs A1 - Arriaga, Patrícia A1 - Batres, Carlota A1 - Beaudry, Jennifer L. A1 - Cova, Florian A1 - Ďurbisová, Simona A1 - Cramblet Alvarez, Leslie D. A1 - Feldman, Gilad A1 - Godbersen, Hendrik A1 - Gottfried, Jaroslav A1 - Haeffel, Gerald J. A1 - Hartanto, Andree A1 - Isloi, Chris A1 - McFall, Joseph P. A1 - Milyavskaya, Marina A1 - Moreau, David A1 - Nosáľová, Ester A1 - Papaioannou, Kostas A1 - Ruiz-Fernandez, Susana A1 - Schrötter, Jana A1 - Storage, Daniel A1 - Vezirian, Kevin A1 - Volz, Leonhard A1 - Weisberg, Yanna J. A1 - Xiao, Qinyu A1 - Awlia, Dana A1 - Branit, Hannah W. A1 - Dunn, Megan R. A1 - Groyecka-Bernard, Agata A1 - Haneda, Ricky A1 - Kielinska, Julita A1 - Kolle, Caroline A1 - Lubomski, Paweł A1 - Miller, Alexys M. A1 - Mækelæ, Martin J. A1 - Pantazi, Mytro A1 - Ribeiro, Rafael R. A1 - Ross, Robert M. A1 - Sorokowska, Agnieszka A1 - Aberson, Christopher L. A1 - Vassiliou, Xanthippi Alexi A1 - Baker, Bradley J. A1 - Bognar, Miklos A1 - Cong, Chin Wen A1 - Danvers, Alex F. A1 - Davis, William E. A1 - Dranseika, Vilius A1 - Dumbravă, Andrei A1 - Farmer, Harry A1 - Field, Andy P. A1 - Forscher, Patrick S. A1 - Graton, Aurélien A1 - Hajdu, Nandor A1 - Howlett, Peter A. A1 - Kabut, Radosław A1 - Larsen, Emmett M. A1 - Lee, Sean T. H. A1 - Legate, Nicole A1 - Levitan, Carmel A. A1 - Levy, Neil A1 - Lu, Jackson G. A1 - Misiak, Michał A1 - Morariu, Roxana E. A1 - Novak, Jennifer A1 - Pronizius, Ekaterina A1 - Prusova, Irina A1 - Rathnayake, Athulya S. A1 - Romanova, Marina O. A1 - Röer, Jan P. A1 - Sampaio, Waldir M. A1 - Schild, Christoph A1 - Schulte-Mecklenbeck, Michael A1 - Stephen, Ian D. A1 - Szecsi, Peter A1 - Takacs, Elizabeth A1 - Teeter, Julia N. A1 - Thiele-Evans, Elian H. A1 - Valeiro-Paterlini, Julia A1 - Vilares, Iris A1 - Villafana, Louise A1 - Wang, Ke A1 - Wu, Raymond A1 - Álvarez-Solas, Sara A1 - Moshontz, Hannah A1 - Buchanan, Erin M. T1 - Registered Replication Report: A Large Multilab Cross-Cultural Conceptual Replication of Turri et al. (2015) T2 - Advances in Methods and Practices in Psychological Science Y1 - 2024 U6 - https://doi.org/10.1177/25152459241267902 SN - 2515-2459 VL - 7 IS - 4 SP - 1 EP - 38 PB - SAGE Publications ER - TY - GEN A1 - Tschammer, Rudi A1 - Buß, Lars A1 - Pożarowska, Emilia A1 - Morales, Carlos A1 - Senanayake, Sanjaya D. A1 - Prieto, Mauricio J. A1 - Tănase, Liviu C. A1 - de Souza Caldas, Lucas A1 - Tiwari, Aarti A1 - Schmidt, Thomas A1 - Niño, Miguel A. A1 - Foerster, Michael A1 - Falta, Jens A1 - Flege, Jan Ingo T1 - High-temperature growth of CeOx on Au(111) and behavior under reducing and oxidizing conditions T2 - The journal of physical chemistry C N2 - Inverse oxide–metal model catalysts can show superior activity and selectivity compared with the traditional supported metal–oxide architecture, commonly attributed to the synergistic overlayer–support interaction. We have investigated the growth and redox properties of ceria nanoislands grown on Au(111) between 700 and 890 °C, which yields the CeO2–Au(111) model catalyst system. We have observed a distinct correlation between deposition temperature, structural order, and oxide composition through low-energy electron microscopy, low-energy electron diffraction, intensity–voltage curves, and X-ray absorption spectroscopy. Improved structural order and thermal stability of the oxide have been achieved by increasing the oxygen chemical potential at the substrate surface using reactive oxygen (O/O2) instead of molecular O2 during growth. In situ characterization under reducing (H2) and oxidizing atmospheres (O2, CO2) indicates an irreversible loss of structural order and redox activity at high reduction temperatures, while moderate temperatures result in partial decomposition of the ceria nanoislands (Ce3+/Ce4+) to metallic cerium (Ce0). The weak interaction between Au(111) and CeOx would facilitate its reduction to the Ce0 metallic state, especially considering the comparatively strong interaction between Ce0 and Au0. Besides, the higher reactivity of atomic oxygen promotes a stronger interaction between the gold and oxide islands during the nucleation process, explaining the improved stability. Thus, we propose that by driving the nucleation and growth of the ceria/Au system in a highly oxidizing regime, novel chemical properties can be obtained. KW - Inverse oxide-metal model catalysts KW - Ceria nanoislands KW - Growth KW - Redox properties KW - Low-energy electron microscopy (LEEM) KW - Low-energy electron diffraction (LEED) KW - Intensity–voltage curves KW - X-ray absorption spectroscopy (XAS) Y1 - 2025 U6 - https://doi.org/10.1021/acs.jpcc.4c08072 SN - 1932-7447 VL - 129 IS - 7 SP - 3583 EP - 3594 PB - American Chemical Society (ACS) CY - Washington, DC ER - TY - GEN A1 - Mubarak, Faisal Ali A1 - Phung, Gia Ngoc A1 - Arz, Uwe A1 - Haddadi, Kamel A1 - Roch-Jeune, Isabelle A1 - Ducournau, Guillaume A1 - Flisgen, Thomas A1 - Doerner, Ralf A1 - Allal, Djamel A1 - Jayasankar, Divya A1 - Stake, Jan A1 - Schmidt, Robin A1 - Fisher, Gavin A1 - Ridler, Nick M. A1 - Shang, Xiaobang T1 - An interlaboratory comparison of on-wafer S-parameter measurements up to 1.1 THz T2 - IEEE Transactions on Terahertz Science and Technology N2 - This article reports on an interlaboratory measurement comparison involving on-wafer S-parameter measurements from 10 GHz to 1.1 THz. Seven laboratories are involved, and each participant has measured an individual reference substrate fabricated from a high-resistivity silicon wafer in the same batch. One- and two-port co-planar waveguide (CPW) structures are designed, simulated, and fabricated. The measurements from 10 GHz to 1.1 THz, extending across six frequency bands, are conducted using different equipment in terms of vendors and specifications (e.g., probe pitch size). Despite such differences, this interlaboratory study has shown a generally good agreement between results from different participants when uncertainties are considered. The comparison with simulated reference values demonstrates agreement within 0.08 for |S11| and 2 dB for |S21| measurements of matched devices up to 1.1 THz. The measurement comparison demonstrates the need for a standardized measurement approach and, with that, a potential to achieve accurate on-wafer CPW measurements up to THz frequencies, underpinning the development of integrated circuits for such high frequencies. Y1 - 2025 U6 - https://doi.org/10.1109/TTHZ.2025.3537461 SN - 2156-3446 SN - 2156-342X VL - 15 IS - 3 SP - 344 EP - 358 PB - Institute of Electrical and Electronics Engineers (IEEE) CY - New York, NY ER - TY - GEN A1 - Bursy, Marcel A1 - Bawamia, Ahmad A1 - Flisgen, Thomas A1 - Goossen-Schmidt, Nora A1 - Luplow, Charleen A1 - Schiemangk, Max A1 - Tyborski, Christoph A1 - Wicht, Andreas T1 - Miniaturised optical isolators for realising micro-integrated photonic modules in quantum technology applications T2 - Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), 23-27 June 2025, Munich, Germany N2 - At the Ferdinand-Braun-Institut (FBH), we have been using our proven hybrid micro-integration technology for more than a decade to realise ultra-compact photonic modules for quantum applications [1]. Our latest innovations: Next-generation laser modules covering an extended wavelength range [2], and newly developed light control units for use in optical atomic clocks [3]. Y1 - 2025 U6 - https://doi.org/10.1109/CLEO/Europe-EQEC65582.2025.11109710 SP - 1 EP - 1 PB - Institute of Electrical and Electronics Engineers (IEEE) CY - New York, NY ER - TY - GEN A1 - Braud, Nicolas A1 - Buß, Lars A1 - Merte, Lindsay Richard A1 - Wallander, Harald A1 - Krisponeit, Jon-Olaf A1 - Schmidt, Thomas A1 - Lundgren, Edvin A1 - Flege, Jan Ingo A1 - Falta, Jens T1 - Growth and oxidation of ultra-thin Pt-Sn layers on Pt(111) by molecular and atomic oxygen T2 - Ultramicroscopy N2 - The preparation of ultra-thin PtSn-alloyed layers by molecular beam epitaxy was studied using low-energy electron microscopy (LEEM) and micro-diffraction (-LEED). Deposition at a sample temperature of 435 °C initially results in the formation of a PtSn/Pt(111) layer showing a (2 × 2) reconstruction. With continued Sn deposition, a PtSn/Pt(111) layer develops, showing a ()R30° reconstruction. An ultra-thin tin oxide was formed from the (2 × 2) surface by exposure to molecular oxygen at temperatures of 500 °C and 590 °C, respectively. LEED shows the evolution of a new surface structure, which could be identified as an incommensurate rectangular reconstruction with lattice parameters of a = (6.4 ± 0.1) Å and b = (8.6 ± 0.1) Å present in three domains rotated by 120° with respect to each other. This structure can be related to the zigzag reconstructions found for similar ultra-thin oxide systems. Contrarily, the ()R30° structure showed no oxide formation even after extensive exposure to molecular oxygen. The usage of atomic oxygen, however, allows for oxidation of this surface and the growth of thicker oxides on both types of overlayers. At 500 °C this process is accompanied by substantial roughening of the surface. KW - Tin KW - Platinum KW - Tin oxide KW - Platinum-tin KW - Oxidation KW - SnOx KW - Ultra-thin films KW - LEED KW - LEEM Y1 - 2025 U6 - https://doi.org/10.1016/j.ultramic.2025.114243 SN - 0304-3991 VL - 278 SP - 1 EP - 11 PB - Elsevier BV CY - Amsterdam ER - TY - GEN A1 - Pożarowska, Emilia A1 - Pleines, Linus A1 - Prieto, Mauricio J. A1 - Tănase, Liviu C. A1 - de Souza Caldas, Lucas A1 - Tiwari, Aarti A1 - Schmidt, Thomas A1 - Falta, Jens A1 - Morales, Carlos A1 - Flege, Jan Ingo T1 - The relationship between Sm alloying and structure sensitivity of ceria(111)- and (100)-oriented nanoislands on Cu(111) T2 - Physical chemistry, chemical physics N2 - We have investigated the complex dynamics of samarium deposition on ceria islands of different orientations, namely (111) and (100), grown side by side on a Cu(111) single-crystal substrate, followed by post-oxidation and annealing under ultra-high vacuum conditions. Only the (100)-oriented ceria islands undergo substantial initial reduction upon samarium deposition at 740 K via a pathway similar to the strong Ce–ceria interfacial interaction, while the (111)-oriented islands remain in the Ce4+ oxidation state. This remarkable structure sensitivity is explained by the different energies required for oxygen vacancy formation for both oxide orientations. Subsequent mild re-oxidation with O2 results in the complete recovery of the Ce4+ oxidation state in the (100)-oriented islands, indicating the complete healing of oxygen vacancies. In contrast, extended annealing at moderate temperatures likely induces persistent samarium incorporation into the cerium oxide matrix. Our results provide new insights into the complex structure–activity relationships in mixed rare-earth metal oxide systems and have promising implications for optimizing catalytic reactions over such compounds in reducing environments. KW - LEEM Y1 - 2025 U6 - https://doi.org/10.1039/D5CP01171J SN - 1463-9076 VL - 27 IS - 29 SP - 15691 EP - 15703 PB - Royal Society of Chemistry (RSC) CY - Cambridge ER - TY - GEN A1 - Ackermann, G. A1 - Peil, M. A1 - Quarz, C. A1 - Schmidt, A. A1 - Halaczkiewicz, M. A1 - Thomas, A. D. A1 - Stegmüller, S. A1 - Richling, E. A1 - Manolikakes, G. A1 - Christmann, M. A1 - Küpper, Jan-Heiner A1 - Schrenk, D. A1 - Fahrer, J. T1 - Molecular dosimetry of estragole and 1′-hydroxyestragole-induced DNA adduct formation, clastogenicity and cytotoxicity in human liver cell models T2 - Archives of toxicology N2 - The phenylpropene estragole (ES) is found in essential oils of herbs and spices, such as bitter fennel and basil. Humans are exposed to ES through the diet and phytomedicines. After its absorption, ES undergoes metabolic activation by CYP1A2 and SULT1A1 in the liver, which can give rise to DNA adducts and hepatocarcinogenesis. Until now, quantitative genotoxicity data for ES in human liver cells are scarce, correlating DNA adduct levels with critical effects such as clastogenicity. Here, we used human HepG2 and HepG2-CYP1A2 cells as well as primary human hepatocytes (PHH) to study the genotoxic, clastogenic and cytotoxic potential of ES and its crucial metabolite 1′-hydroxyestragole (1′OH-ES). In addition, primary rat hepatocytes (PRH) were used for selected endpoints. Treatment of HepG2-CYP1A2 cells with ES (0–2 mM) led to the concentration-dependent formation of E3′- N 2 -dG adducts. Apart from a moderate γH2AX induction, neither p53 accumulation nor cytotoxicity was observed. However, clastogenicity was demonstrated at ES concentrations ≥ 1 mM. Incubation of HepG2 cells with 1′OH-ES (0—35 µM) led to 10–50-fold higher E3′- N 2 -dG adduct levels compared to equimolar ES concentrations. Furthermore, 1′OH-ES caused γH2AX formation, p53 accumulation and cytotoxicity, which was confirmed in PHH. In agreement, 1′OH-ES induced clastogenicity at concentrations ≥ 25 µM. Molecular dosimetry revealed that a certain E3′- N 2 -dG adduct level is required to trigger clastogenicity and cytotoxicity. This was confirmed by Benchmark Concentration (BMC) modelling, showing that the BMC for clastogenicity is 12–17-fold higher than the respective BMC for DNA adduct formation. Our data indicate that a threshold level of DNA adducts is required, both in rat and human liver cells, to trigger markers of clastogenicity. These levels are unlikely to be reached in humans following chronic ES exposure through phytomedicines or the diet. KW - Plant toxin KW - Phenylpropanoids KW - Estragole KW - Human hepatocytes KW - Liver damage KW - Cytotoxicity KW - Genotoxicity KW - Clastogenicity KW - Concentration–response modelling Y1 - 2025 U6 - https://doi.org/10.1007/s00204-025-04084-2 SN - 0340-5761 SN - 1432-0738 VL - 99 IS - 9 SP - 3769 EP - 3785 PB - Springer CY - Berlin ; Heidelberg ER -