Magnetic States in Quantum Carbon and Rare-Earth Porphyrin Units

Graphene, a well-defined two-dimensional honeycomb network of carbon atoms, shows impressive electrical and mechanical properties [1]. Quasi-one-dimensional nanoribbons of graphene have emerged particular interest. By introducing magnetic edges in graphene nanoribbons (GNRs), for example, ferromagnetic couplings and superior spin filtering are predicted [2,3], making them promising materials for future spintronic devices. Moreover, graphenoid systems can show large coherence times in the submillisecond regime, making them interesting candidates for quantum computation [4].<br/><br/>By utilizing an ultra-clean synthetic bottom-up approach, we were able to create graphene nanoribbons with great purity [5]. We have shown previously that spin-polarized edges can be detected via time-resolved electron paramagnetic resonance (EPR) spectroscopy by decorating the GNR edges with organic radicals, which serve as spin injectors [6]. It would be now interesting to see how high-spin complexes, as provided by rare earths, affect the magnetic edges. Here, I will show a novel class of GNRs decorated with metallic porphyrin systems, as well as other zero-dimensional quantum carbon units with enhanced properties and submillisecond coherence times. Using EPR spectroscopy, we gain information on the spin dynamics of these systems, and quantify fundamental properties such as phase-memory times and spin-lattice relaxation parameters.<br/><br/>___________________<br/>[1] Geim, A. K., Novoselov, K.S., <i>Nat. Mater.</i>, <b>2007</b>, 6, 183-191.<br/>[2] Saffarzadeh, A., Farghadan, R., <i>Appl. Phys. Lett.</i>, <b>2011</b>, 98, 023106.<br/>[3] Farghadan, R., Saffarzadeh, A., <i>RSC Adv.</i>, <b>2015</b>, 5, 87411.<br/>[4] Lombardi, F., et al., <i>Science,</i> <b>2019</b>, 366, 1107-1110.<br/>[5] Narita, A., et al., <i>Nat. Chem.</i>, <b>2014</b>, 6, 126-131.<br/>[6] Slota, M., et al., <i>Nature</i>, <b>2018</b>, 557, 691-695.