Regensburg 2025 – scientific programme
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O: Fachverband Oberflächenphysik
O 45: Poster Spins on Surfaces at the Atomic Scale
O 45.7: Poster
Tuesday, March 18, 2025, 18:00–20:00, P2
Investigation of the Kondo effect in complex, artificially built, single molecule structures — •Lars Pütz1, Daria Sostina1, Taner Esat1,2, Stefan Tautz1,2,3, Ruslan Temirov1,4, and Markus Ternes1,2,5 — 1Peter-Grünberg-Institute for Quantum Nanoscience, Research Center Jülich, 52425 Jülich, Germany — 2Jülich Aachen Research Alliance, Fundamentals of Future Information Technology, 52425 Jülich, Germany — 3Institute of Physics IV, RWTH Aachen University, 52074 Aachen, Germany — 4Institute of Physics II, University of Cologne, 50937 Cologne, Germany — 5Institute of Physics IIB, RWTH Aachen University, 52074 Aachen, Germany
In engineered spin systems, strongly correlated many-body phenomena such as nontrivial topology, Kondo screening and highly correlated long-range states can be constructed and studied by site-selective measurements with scanning tunneling microscope (STM) tips [C. Zhao et al., Nat. Nanotech. 2024]. Here we show how many-body phenomena evolve by controlled manipulation of NTCDA molecules on Ag(111) using the tip of an STM. Building small clusters of 2-5 molecules and tuning their spatial geometry reveals complexly patterned Kondo resonances and, in addition, an electric field-dependent strong increase in conductance, which we attribute to the collapse of Kondo correlations [S. Arabi et al., arXiv 2022]. Single NTCDA molecules on the other hand show no detectable spin signature, despite the clear formation of Kondo resonances in clusters where their high symmetry with respect to the surface is broken.
Keywords: Kondo resonance; Quantum phase transition; Single spin; Electric field; Molecular network