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O: Fachverband Oberflächenphysik
O 14: Poster Session I: Nanostructures at surfaces I
O 14.1: Poster
Monday, March 1, 2021, 10:30–12:30, P
Length dependent symmetry in narrow chevron-like graphene nanoribbons — •Koen Houtsma1, Mihaela Enache1, Remco Havenith1,2, and Meike Stöhr1 — 1Zernike Institute for Advanced Materials, University of Groningen, 9747AG Groningen, the Netherlands — 2Strating Institute for Chemistry, University of Groningen, 9747AG Groningen, the Netherlands
Graphene nanoribbons (GNRs) are an exciting material due to their excellent and tunable electronic properties. For instance, GNRs with armchair edge possess a width-dependent band gap, whereas zigzag GNRs are expected to host spin-polarized edge states and be semimetallic [1]. Previously, narrow chevron-like GNRs, which host a combination of zigzag and armchair edge terminations, were fabricated on a Au(111) substrate from the prochiral precursor 6,12-dibromochrysene through a combination of Ullmann-type coupling and cyclodehydrogenation [2]. Depending on the number of monomer units the ribbons are made of, an even and an odd number lead to a mirror and a point symmetric ribbon. Using scanning tunneling spectroscopy we investigated the potential effect of this length dependent symmetry on the electronic properties. In addition, we observed that through a common coupling defect bends are formed in the ribbons. We characterized these bends using a combination of high-resolution scanning tunneling microscopy and spectroscopy. It turned out the bends are based on the formation of both a five- and six-membered ring and that their electronic properties are altered. [1] K. Nakada et al., Phys. Rev. B 54, 17954 (1996) [2] T.A. Pham et al., Small 13, 1603675 (2017)