Tailoring π -- d $\pi {\text{--}}d$ Magnetic Interactions in Metallated Porphyrin Nanotapes

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Molecular assemblies based on porphyrins (Pors) with magnetic metal ions are platforms for studying magnetic interactions.
• The interplay between π-conjugated ligands and transition metal d-orbitals influences magnetic properties.

Purpose of the Study:

• To synthesize and characterize π-extended porphyrin nanotapes (PorNTs) with Fe and Co on Au(111).
• To investigate the distinct magnetic behaviors and electronic properties of Fe- and Co-based PorNTs.

Main Methods:

• On-surface synthesis under ultra-high vacuum.
• Atomic structure resolution using scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM).
• Differential conductance (dI/dV) measurements interpreted by density functional theory (DFT) calculations and theoretical modeling.

Main Results:

• FePorNTs show strong Fe-ligand ferromagnetic coupling and weak Fe-Fe antiferromagnetic coupling.
• CoPorNTs exhibit stronger Co-Co antiferromagnetic exchange and weaker Co-ligand coupling, with Kondo screening at ligand sites.
• Distinct magnetic behaviors arise from metal centers, ligands, and substrate interactions.

Conclusions:

• Porphyrin nanotapes with magnetic metal ions are versatile building blocks for low-dimensional magnetism.
• These systems hold potential for future spintronic and quantum-material applications.
• Metal centers significantly influence the magnetic and electronic properties of PorNTs.