Low-temperature macromolecular physics at interfaces: From Heisenberg spin-chains to topological phonon-chains

Atomically-precise, carbon nanomaterials at interfaces are a fertile ground for the exploration of exemplary and emerging physical phenomena in condensed matter [1]. Here, we present a summary of properties which we have studied in supramolecular and macromolecular carbon nanomaterials at interfaces, based on characterization by means of low-temperature scanning probe spectroscopy, microscopy, transport and density functional theory calculations. We will introduce on-surface azomethine ylide cycloadditions [2] serving as paradigmatic building blocks for antiaromatic chains and spin-chains. We will explore how the electronic properties of N-containing triangulenes on transition-metal dichalcogenides, define nanostructures for the investigation of chalcogen-organic networks and their flat-bands [3], whereas sp3-carbon ligands [4] could lead to universal phonon topology decoupled from substrates [5]. Finally, we’ll present diverse efforts for enhancing conductivity in carbon nanomaterials, such as hydrogenation of hexabenzocoronene layers, diamantane photodebromination reactions, as well as anthracene-based pyrolyzed molecular nanocrystals [6]. These studies, together with advancing the physics of N-containing sp2- and sp3-carbon nanomaterials, may usher in an era of supramolecular, quantum soft matter physics and surfacing applications.

References

[1] K. Müllen, C.-A. Palma “Materials with atomic precision” Inside E-MRS World 2023, 2, 15-16
[2] Wang, X.-Y. et al. Nature Commun. 2017, 8, 1948; Riss, A. et al. Nature Commun. 2020, 11, 1490; Gao, Y. et al. Nature Commun. 2022, 13, 6146, Fu, X., et al. Nature Synthesis 2025. Li, J. et al. “Topological Woodward-Hoffmann classification for radical cycloadditions in polycyclic aromatic azomethine ylides” Research Square 2024; Wang, Y. et al. “Thermal spin-crossover and temperature-dependent zero-field splitting in magnetic nanographene chains” arXiv:2407.20996, 2024
[3] Jin, Y. et al. “Flat-band forming chalcogen-organic networks” 2024
[4] Wang, Z. et al. ACS Appl. Nano. Mater. 2020, 3, 11752
[5] Cojal González, J.D. et al., Nature Commun. 2024, 15, 10674; C.-A. Palma J. Phys. Chem. Lett. 2021, 12, 454−462
[6] Wang, Y. et al. ACS Nano. 2023, 17, 19, 18832; Zhang, X. et al. Nature Commun. 2022, 13, 442