Dual Topology States in Two-Dimensional Buckybowl Supramolecular Crystal of Sumanene.

Bowl-shaped polycyclic conjugated aromatic hydrocarbons have received tremendous attention because of their structural diversity and potential functionalization of their derivatives in fields such as spintronics, energy storage, etc. However, the topological electronic states of these organic buckybowl sumanenes have been less explored. Here we study the first- and higher-order topological states of a two-dimensional buckybowl supramolecular crystal of sumanene using density functional theory calculations and Wannier-based tight-binding models. A higher-order topological insulating state at the Fermi level is unveiled, which is demonstrated by the fractional corner charge and localized corner states in triangular nanodisks. The periodic arrangement of concave buckybowl sumanene yields a prototypical breathing Kagome lattice that hosts valley-contrasting Berry physics in its first conduction bands. The rationally designed one-dimensional atomic boundary, namely, sumanene zigzag edge, hosts the topologically protected kink states. This work establishes a typical example of coexisting first- and higher-order topology in an organic buckybowl sumanene, opening new avenues for engineering hierarchical topological phenomena through molecular curvature control in complex organic frameworks.