Electronic and magnetic properties in monolayer/substrate interfaces of metallofullerene single molecule magnet Tb2@C79N featuring single-electron Tb-Tb bond

• Applicant: Dr. Alexey A. Popov
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation ; Experimental Condensed Matter Physics
• Term: from 2020 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 448005669

• Final Report Year: 2024

Final Report Abstract

The project was aimed at in-depth understanding of electronic and magnetic properties of dimetallofullerene with single-electron lanthanide-lanthanide bonds in interfaces of their monolayers with different substrates. In the bulk form, such dimetallofullerenes demonstrate singlemolecule magnetism with broad magnetic hysteresis and high blocking temperatures of magnetization, and in this project, we studied deposition of their thin films and characterization thereof by spectroscopic techniques and scanning-tunneling microscopy. Magnetic behavior of monolayers was then analyzed using X-ray magnetic circular dichroism. Submonolayers of Tb2@C79N on Cu, Au, MgO/Ag, and h-BN/Rh were prepared by evaporation in ultra-high vacuum. Unexpectedly, XMCD studies revealed that on surface molecules showed reduced hysteresis combined with anti-ferromagnetic coupling. These properties were ascribed to the trapping of an electron by the singly-occupied Tb-Tb orbital, which changed the coupling of Tb magnetic moments. Deposition of Tb 2@C80(CH2Ph) monolayers on graphene and graphite was accomplished by self-assembly from solution, for which the fullerene surface was functionalized with pyrene anchor groups. These layers exhibited magnetic hysteresis up to 28 K, which is the highest hysteresis temperature for surface-supported single-molecule magnets. Monolayers of Dy2@C80(CH2Ph), deposited by electrospray technique, also showed excellent magnetic properties and allowed visualization of the electron transfer through the single-occupied metal-metal bonding orbital.

Publications

• Electrophilic Trifluoromethylation of Dimetallofullerene Anions en Route to Air-Stable Single-Molecule Magnets with High Blocking Temperature of Magnetization. Journal of the American Chemical Society, 143(43), 18139-18149.
  Wang, Yaofeng; Velkos, Georgios; Israel, Noel Jens; Rosenkranz, Marco; Büchner, Bernd; Liu, Fupin & Popov, Alexey A.
  
• Exceptionally High Blocking Temperature of 17 K in a Surface‐Supported Molecular Magnet. Advanced Materials, 33(40).
  Paschke, Fabian; Birk, Tobias; Enenkel, Vivien; Liu, Fupin; Romankov, Vladyslav; Dreiser, Jan; Popov, Alexey A. & Fonin, Mikhail
  
• Imaging the Single‐Electron Ln–Ln Bonding Orbital in a Dimetallofullerene Molecular Magnet. Small, 18(3).
  Paschke, Fabian; Birk, Tobias; Avdoshenko, Stanislav M.; Liu, Fupin; Popov, Alexey A. & Fonin, Mikhail
  
• Robust Single Molecule Magnet Monolayers on Graphene and Graphite with Magnetic Hysteresis up to 28 K. Advanced Functional Materials, 31(48).
  Spree, Lukas; Liu, Fupin; Neu, Volker; Rosenkranz, Marco; Velkos, Georgios; Wang, Yaofeng; Schiemenz, Sandra; Dreiser, Jan; Gargiani, Pierluigi; Valvidares, Manuel; Chen, Chia‐Hsiang; Büchner, Bernd; Avdoshenko, Stanislav M. & Popov, Alexey A.
  
• Metamagnetic transition and a loss of magnetic hysteresis caused by electron trapping in monolayers of single-molecule magnet Tb2@C79N. Nanoscale, 14(27), 9877-9892.
  Koutsouflakis, Emmanouil; Krylov, Denis; Bachellier, Nicolas; Sostina, Daria; Dubrovin, Vasilii; Liu, Fupin; Spree, Lukas; Velkos, Georgios; Schimmel, Sebastian; Wang, Yaofeng; Büchner, Bernd; Westerström, Rasmus; Bulbucan, Claudiu; Kirkpatrick, Kyle; Muntwiler, Matthias; Dreiser, Jan; Greber, Thomas; Avdoshenko, Stas M.; Dorn, Harry & Popov, Alexey A.
  
• Monometallic Endohedral Azafullerene. Journal of the American Chemical Society, 144(47), 21587-21595.
  Xiang, Wenhao; Jiang, Xiaole; Yao, Yang-Rong; Xin, Jinpeng; Jin, Huaimin; Guan, Runnan; Zhang, Qianyan; Chen, Muqing; Xie, Su-Yuan; Popov, Alexey A. & Yang, Shangfeng
  
• Controlled Nanoplatelet Deposition of 2D Chromium Trihalide Solid Solutions. Chemistry of Materials, 35(11), 4136-4148.
  Froeschke, Samuel; Yasmen, Nadia; Popov, Alexey A.; Schiemenz, Sandra; Wolf, Daniel; Giebeler, Lars; Hantusch, Martin; Gräßler, Nico; Büchner, Bernd; Schmidt, Peer & Hampel, Silke
  
• Inferring the Dy-N axis orientation in adsorbed DySc 2 N@C80 endofullerenes by linearly polarized xray absorption spectroscopy. Physical Review Materials, 7(8).
  Sagehashi, Ryunosuke; Lee, Wei Chuang; Liu, Fupin; Popov, Alexey A.; Muntwiler, Matthias; Delley, Bernard; Krüger, Peter & Greber, Thomas
  
• Understanding the chemistry of 2D rhodium trihalide solid solutions: tuning of optical properties and nanocrystal deposition. 2D Materials, 10(3), 035011.
  Froeschke, Samuel; Schroth, Karl-Georg; Steiner, Udo; Popov, Alexey; Schiemenz, Sandra; Wolf, Daniel; Giebeler, Lars; Gräßler, Nico; Büchner, Bernd; Schmidt, Peer & Hampel, Silke
  
• Correlation of Work Function and Conformation of C80 Endofullerenes on h‐BN/Ni(111). Advanced Materials Interfaces, 11(8).
  Stania, Roland; Seitsonen, Ari Paavo; Jung, Hyunjin; Kunhardt, David; Popov, Alexey A.; Muntwiler, Matthias & Greber, Thomas