Magnetic Excitations in Ferromagnetically Coupled Spin-1 Nanographenes

Area of Science:

• Materials Science
• Organic Chemistry
• Condensed Matter Physics

Background:

• High-spin molecular building blocks are essential for creating novel magnetic materials.
• Nanographenes offer a tunable platform for engineering magnetic interactions.
• Controlling ferromagnetic coupling in nanographenes is key for advanced materials.

Purpose of the Study:

• To explore the spin properties of ferromagnetically coupled triangulenes.
• To synthesize and characterize covalently bonded triangulene dimers and trimers.
• To investigate the potential of these structures for creating 1D and 2D magnetic materials.

Main Methods:

• In-solution synthesis of molecular precursors.
• On-surface synthesis on Au(111).
• Inelastic electron tunneling spectroscopy (IETS) for characterizing magnetic excitations.
• Heisenberg model for analyzing magnetic exchange interactions.

Main Results:

• Successful synthesis of covalently bonded triangulene dimers and trimers.
• IETS confirmed quintet-to-triplet excitation and spin-spin scattering in triangulene dimers.
• The Heisenberg model accurately described inter-triangulene ferromagnetic exchange.
• Model validation for larger triangulene systems.

Conclusions:

• Ferromagnetically coupled triangulenes are viable building blocks for magnetic nanographenes.
• This work provides a foundation for designing carbon nanomaterials with complex magnetic ground states.
• The findings open new avenues for creating advanced 1D and 2D magnetic materials.