Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 52: Focus Session: Spins on Surfaces studied by Atomic Scale Spectroscopies V
O 52.8: Vortrag
Mittwoch, 20. März 2024, 17:00–17:15, MA 004
Strong exchange interactions between open-shell nanographenes and a rare earth-gold surface alloy — •Nicolo' Bassi1, Feifei Xiang1, Nils Krane1, Carlo Pignedoli1, Jan Jan Wilhelm2, Michal Juríček3, Roman Fasel1, and Pascal Ruffieux1 — 1Empa, Duebendorf, Switzerland — 2Institute of Theoretical Physics, Regensburg, Germany — 3University of Zurich, Zurich, Switzerland
Rare-earth-based intermetallic compounds belong to a family of novel substrates, which is becoming a promising platform to control properties of nanomaterials via specific surface-adsorbates interactions. Different combinations, including GdAu2(1) and TbAu2(2), have been so far studied. They are all characterized by a ordered hexagonal superstructure with similar lattice constants. Here, we investigate various open-shell nanographenes on TbAu2 alloy by means of scanning tunneling techniques. For on-surface synthesized 7 armchair graphene nanoribbons (7-AGNRs), we find that the predicted spin properties of the end states are indeed conserved on TbAu2. Thanks to its lower workfunction, the 7-AGNRs are uncharged and the occupied and unoccupied end states have a spin polarization-induced energy splitting of 1.4eV. In addition, we investigated phenalenyl, the smallest open-shell molecule with spin S = 1/2(4). Low bias spectroscopy reveals a splitting of more than 20mV, which we assign to the exchange interaction between the molecular spin and Tb atoms of the surface layer. These results shows a new substrate for studying different open-shell C structures. 1 Corso, M. et al. ACS Nano 4,(2010). 2 Que, Y. et al. J. Phys. Chem. Lett. 11,(2020). 3 Turco, E. et al. jJACS Au (2023)
Keywords: rare earh surface alloy; open-shell nanographenes; workfunction matching; scanning tunneling spectroscopy; on-surface synthesis