We extensively characterize the electronic structure of ultranarrow graphene nanoribbons (GNRs) with armchair edges and zigzag termini that have five carbon atoms across their width (5-AGNRs), as synthesized on Au(111). Scanning tunneling spectroscopy measurements on the ribbons, recorded on both the metallic substrate and a decoupling NaCl layer, show well-defined dispersive bands and in-gap states. In combination with theoretical calculations, we show how these in-gap states are topological in nature and localized at the zigzag termini of the nanoribbons. In addition to rationalizing the driving force behind the topological class selection of 5-AGNRs, we also uncover the length-dependent behavior of these end states which transition from singly occupied spin-split states to a closed-shell form as the ribbons become shorter. Finally, we demonstrate the magnetic character of the end states via transport experiments in a model two-terminal device structure in which the ribbons are suspended between the scanning probe and the substrate that both act as leads.
J. Lawrence, P. Brandimarte, A. Berdonces-Layunta, M. S. G. Mohammed, A. Grewal, C. C. Leon, D. Sánchez-Portal, and D. G. de Oteyza. Probing the Magnetism of Topological End States in 5-Armchair Graphene Nanoribbons. ACS Nano 14, 4 (2020)
© 2020 American Chemical Society
Type of paper:
We extensively characterize the electronic structure of ultranarrow graphene nanoribbons (GNRs) with armchair edges and zigzag termini that have five carbon atoms across their width (5-AGNRs), as synthesized on Au(111). Scanning tunneling spectroscopy measurements on the ribbons, recorded on both the metallic substrate and a decoupling NaCl layer,
https://pubs.acs.org/doi/abs/10.1021/acsnano.9b10191