Massive Dirac fermion behavior in a low bandgap graphene nanoribbon near a topological phase boundary
Creators
- 1. Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
- 2. Department of Physics, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
- 3. Rensselaer Polytechnic Institute, Department of Physics, Applied Physics and Astronomy, Troy, NY, 12180 USA
- 4. Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
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Description
Graphene nanoribbons (GNRs) have attracted much interest due to their largely modifiable electronic properties. Manifestation of these properties requires atomically precise GNRs which can be achieved through a bottom–up synthesis approach. This has recently been applied to the synthesis of width‐modulated GNRs hosting topological electronic quantum phases, with valence electronic properties that are well captured by the Su–Schrieffer–Heeger (SSH) model describing a 1D chain of interacting dimers. In this record we provide data to support our recent publication where we demonstrate that ultralow bandgap GNRs with charge carriers behaving as massive Dirac fermions can be realized when their valence electrons represent an SSH chain close to the topological phase boundary, i.e., when the intra‐ and interdimer coupling become approximately equal. Such a system has been achieved via on‐surface synthesis based on readily available pyrene‐based precursors and the resulting GNRs are characterized by scanning probe methods. The pyrene‐based GNRs (pGNRs) can be processed under ambient conditions and incorporated as the active material in a field effect transistor. A quasi‐metallic transport behavior is observed at room temperature, whereas at low temperature, the pGNRs behave as quantum dots showing single‐electron tunneling and Coulomb blockade. This study may enable the realization of devices based on carbon nanomaterials with exotic quantum properties.
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References
Journal reference Q. Sun, O. Gröning, J. Overbeck, O. Braun, M. L. Perrin, G. Borin Barin, M. El Abbassi, K. Eimre, E. Ditler, C. Daniels, V. Meunier. C. A. Pignedoli, M. Calame, R. Fasel, P. Ruffieux, Adv. Mater. 32, 1906054 (2020), doi: 10.1002/adma.201906054