Evolution of the Topological Energy Band in Graphene Nanoribbons

Topological theory has been recently applied in graphene nanoribbons (GNRs) and predicts the existence of topological quantum states junctions connecting GNRs different classes. Through periodic alignment along a GNR backbone, frontier electronic bands with tunable band gaps widths could be generated. In this work, we demonstrate evolution by fabricating structures hosting single junction, dimerized junctions, multiple coupled on-surface synthesis, which guarantees atomic precision these nanostructures. Their structural properties are investigated scanning tunneling microscopy spectroscopy supported tight-binding theory. The 1D superlattice junction can described an effective two-band Su–Schrieffer–Heeger (SSH) type model considering two alternating coupling motifs.