Regensburg 2019 – scientific programme

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O: Fachverband Oberflächenphysik

O 99: Focus Session: Spins on Surfaces III (joint session O/MA)

O 99.2: Talk

Friday, April 5, 2019, 11:00–11:15, H24

Exploring magnetic frustration in atomically engineered closed chains — •Jeremie Gobeil, David Coffey, Shang-Jen Wang, and Alexander F. Otte — Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands

Modelling quantum systems with a large number of degrees of freedom can be a daunting task from a computational standpoint. Scanning Tunneling Microscopy (STM) offers an alternative path by enabling atom-by-atom engineering and probing of such systems. Spin-Polarized STM (SP-STM) can provide direct insight into a system’s spin configuration, while at the same time providing a tunable interaction parameter. This enables the study of frustrated spin systems, which pose a particular modelling challenge as they are governed by a delicate balance of competing interactions.

Here we present the study of such a frustrated spin system, consisting in closed chains of single iron atoms assembled on a single nitride layer grown on Cu₃Au(100). As in the similar Cu₂N system, the nitride layer provides a uniaxial framework with different ferromagnetic and antiferromagnetic interatomic couplings depending on the relative position on the lattice. This allows us to assemble closed loop chains with an odd number of antiferromagnetic couplings, leading to frustration. We explore the role of an external magnetic field, interatomic exchange, as well as the exchange interaction with the spin-polarized tip in the stabilization of the resulting spin configuration.