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arXiv · 2409.20312

Spin Excitations of High Spin Iron(II) in Metal-Organic Chains on Metal and Superconductor

Jung-Ching Liu·Chao Li·Outhmane Chahib·Xing Wang·Simon Rothenbühler·Robert Häner·Silvio Decurtins·Ulrich Aschauer·Shi-Xia Liu·Ernst Meyer·Rémy Pawlak
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Abstract

Many-body interactions in metal-organic frameworks are fundamental for emergent quantum physics. Unlike their solution counterpart, magnetization at surfaces in low-dimensional analogues is strongly influenced by magnetic anisotropy induced by the substrate and still not well understood. Here, we use on-surface coordination chemistry to synthesize on Ag(111) and superconducting Pb(111) an iron-based spin chain by using pyrene-4,5,9,10-tetraone precursors as ligands. Using low-temperature scanning probe microscopy, we compare their structures and low-energy spin excitations of coordinated Fe atoms with high S = 2 spin-state. Although the chain and coordination centers are identical on both substrates, the long-range spin-spin coupling due to a superexchange through the ligand observed on Ag is absent on Pb(111). We ascribe this reduction of spin-spin interactions on Pb to the depletion of electronic states around the Fermi level in the Pb(111) superconductor as compared to silver.

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Jung-Ching Liu, Chao Li, Outhmane Chahib, Xing Wang, Simon Rothenbühler, Robert Häner, Silvio Decurtins, Ulrich Aschauer, Shi-Xia Liu, Ernst Meyer, Rémy Pawlak. 2024-09-30. Spin Excitations of High Spin Iron(II) in Metal-Organic Chains on Metal and Superconductor. https://doi.org/10.1002/advs.202412351

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