Topological properties in graphene nanoribbons

With the advent of precision chemistry, the atomically precise synthesis of graphene nanoribbons (GNRs) with well-defined widths, edge structures, and terminations has become achievable. Alongside GNRs possessing zigzag or armchair edge terminations, more intricate edge configurations have been realized. These edges exert a significant influence on the electronic properties of GNRs.

In this project, we explore the direct correlation between the structural parameters defining cove-edge zigzag nanoribbons (ZGNR-Cs) and their electronic states, while examining the impact of termination effects. In certain cases, ZGNR-Cs exhibit topologically non-trivial states, influenced by ribbon terminations and manifested through the positions of inversion centers within the unit cells. We establish a direct relationship between structural and electronic topology in these systems and delineate simple guidelines for designing cove-edged nanoribbons of diverse electronic characteristics, with varying band gap sizes and the presence or absence of topological edge states. Furthermore, we observe that similar principles apply to other types of GNRs.

Publications:

F. M. Arnold, T.-J. Liu, A. Kuc, T. Heine, Structure-Imposed Electronic Topology in Cove-Edge Graphene Nanoribbons, Phys. Rev. Lett. 129, 216401 (2022). DOI: https://doi.org/10.1103/PhysRevLett.129.216401.