CPHN 1 emerged as an intrinsic metal with near-ballistic transport, with conductance approaching one quantum in measurements on atomically precise carbon pentaheptite nanoribbons.
The team built 2 ribbon types through on-surface hierarchical synthesis, laterally fusing aligned polypentalene chains transformed from pre-synthesized polycyclooctadiene chains.
CPHN 2, made from the same non-benzenoid carbon framework, behaved instead as a narrow-bandgap semiconductor, showing how edge orientation changes the electronic state.
The work realizes a theorized pentaheptite-based carbon metal first proposed in 1996 and points to bottom-up all-carbon quantum wires, though the authors say synthesis still needs optimization for devices.