Engineering of spin states in porphyrin - graphene nanoribbon hybrid systems

• Applicant: Dr. Feifei Xiang
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Solid State and Surface Chemistry, Material Synthesis
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 452269487

The spin degree of freedom in semiconducting materials is expected to play a pivotal role in next-generation information technologies. However, the development of technologies that harness the spin degree of freedom (‘spintronics’) faces various challenges related to the generation of spin-polarized carriers, spin injection across interfaces, coherent spin transport over long distances, and manipulation and detection of spin states, to name only a few. In the last decade, finite sized graphene flakes (nanographenes) and narrow strips of graphene (graphene nanoribbons, GNRs) hosting spin-polarized edge states have become promising candidates for spintronic applications, with predicted long spin relaxation and decoherence times, long spin correlation lengths and the feasibility of electric field control of spin transport. Furthermore, theoretical studies have suggested that incorporation of magnetic transition metal (TM) atoms into GNRs provides manifold opportunities for tuning the electronic and spin states of the resulting hybrid materials. However, the experimental realization of correspondingly modified GNRs has remained elusive. In this project, a conceptually straightforward route to the incorporation of TM atoms in molecularly designed GNRs will be explored. Using the on-surface synthesis approach to the bottom-up fabrication of GNRs developed by the host team, porphyrin macrocycles will be embedded within GNR segments. The heterocyclic cavity allows them to host TM atoms, resulting in a subtle interplay of magnetic properties of GNR backbone and embedded metalloporphyrins. By investigating such hybrid systems containing different TM atom species as well as different width, length and edge topology of GNR segments, this project will establish a fundamental understanding of the nanoscale physics of metalloporphyrin-GNR hybrids and provide a solid basis for the design of such materials for applications in spintronic devices.

• DFG Programme: WBP Fellowship
• International Connection: Switzerland
• Host: Professor Dr. Roman Fasel