Magnetic Excitations of Isolated and Interconnected Complexes on a Superconductor

Area of Science:

• Condensed Matter Physics
• Surface Science
• Molecular Magnetism

Background:

• Superconducting surfaces provide unique platforms for studying quantum phenomena.
• Iron(II) porphyrins are molecular complexes with interesting magnetic properties.
• Controlling molecular magnetism at the nanoscale is crucial for future electronic devices.

Purpose of the Study:

• To investigate the magnetic quantum states of iron(II) porphyrin on a superconducting lead surface.
• To understand the influence of adsorption configuration and intermolecular interactions on molecular magnetism.
• To demonstrate control over magnetic excitations in molecular systems on superconductors.

Main Methods:

• Low-temperature scanning tunneling microscopy (LT-STM) for atomic-scale imaging and spectroscopy.
• Ullmann coupling for controlled preparation of molecular networks.
• Density functional theory (DFT) calculations for theoretical interpretation of magnetic properties.

Main Results:

• Isolated iron(II) porphyrin molecules exhibited two distinct adsorption configurations with unique magnetic excitations (Yu-Shiba-Rusinov states and spin excitations).
• Magnetic properties were influenced by molecular magnetic anisotropy and exchange coupling with the superconducting substrate.
• Molecular networks displayed diverse structures and properties due to strong intermolecular interactions.
• Demonstrated tunable control over the magnetic quantum states of the molecular complex.

Conclusions:

• The adsorption configuration and intermolecular interactions significantly impact the magnetic behavior of iron(II) porphyrin on superconductors.
• Scanning tunneling microscopy and DFT calculations provide insights into the magnetic excitations and anisotropy.
• This study highlights the potential of superconducting surfaces for controlling molecular magnetism at the quantum level.