Liu Jung-Ching, Li Chao, Chahib Outhmane, Wang Xing, Rothenbühler Simon, Häner Robert, Decurtins Silvio, Aschauer Ulrich, Liu Shi-Xia, Meyer Ernst, Pawlak Rémy
Department of Physics, University of Basel, Klingelbergstrasse 82, Basel, 4056, Switzerland.
Department of Chemistry, Biochemistry and Pharmaceutical Sciences, W. Inäbnit Laboratory for Molecular Quantum Materials, University of Bern, Freiestrasse 3, Bern, 3012, Switzerland.
Adv Sci (Weinh). 2025 Feb;12(7):e2412351. doi: 10.1002/advs.202412351. Epub 2024 Dec 24.
Many-body interactions in metal-organic frameworks (MOFs) are fundamental for emergent quantum physics. Unlike their solution counterpart, magnetization at surfaces in low-dimensional analogues is strongly influenced by magnetic anisotropy (MA) induced by the substrate and still not well understood. Here, on-surface coordination chemistry is used to synthesize on Ag(111) and superconducting Pb(111) an iron-based spin chain by using pyrene-4,5,9,10-tetraone (PTO) precursors as ligands. Using low-temperature scanning probe microscopy, their structures and low-energy spin excitations of coordinated Fe atoms are compared 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 on Ag is not experimentally observed on Pb(111). This reduction of spin-spin interactions on Pb in tunneling spectra is ascribed to the depletion of electronic states around the Fermi level of the Pb(111) superconductor as compared to silver.
金属有机框架（MOF）中的多体相互作用是新兴量子物理学的基础。与它们在溶液中的对应物不同，低维类似物表面的磁化受到衬底诱导的磁各向异性（MA）的强烈影响，并且仍然没有得到很好的理解。在这里，表面配位化学被用于在Ag(111)和超导Pb(111)上通过使用芘-4,5,9,10-四酮（PTO）前体作为配体来合成铁基自旋链。使用低温扫描探针显微镜，将它们的结构和配位Fe原子的低能自旋激发与高S = 2自旋态进行比较。尽管在两个衬底上链和配位中心是相同的，但在Pb(111)上没有通过实验观察到通过Ag上的配体进行超交换引起的长程自旋-自旋耦合。隧道谱中Pb上自旋-自旋相互作用的这种减少归因于与银相比，Pb(111)超导体费米能级周围电子态的耗尽。
