Designer topological flat bands in one-dimensional armchair graphene antidot lattices

We report a viable strategy to realize topological flat bands in one-dimensional armchair graphene antidot lattices. The quantum destructive interference effect leads to largely quenched intra-antidot hopping with nearly zero values, creating flat bands with a nontrivial topology, as unveiled by an effective Su-Schrieffer-Heeger model under extreme conditions. As a proof of concept, we demonstrate our approach in the on-surface synthesized porous seven-carbon-wide armchair graphene nanoribbons with periodic divacancy-type antidots, and showcase the robust flatness of the designer topological flat bands with a high tunability through strain and structural engineering which are investigated by combining tight-binding and density functional theory calculations with scanning probe microscopy measurements. We show that such available one-dimensional graphene nanoribbons can provide a rich platform for exploiting novel physics at the confluence of strong correlation and topology, opening up new avenues for research in the field of topological materials and their potential applications in quantum devices.