Smooth and jump-like metal-dielectric transitions in single-walled carbon nanotubes under functionalization.

We examine at the DFT level of theory the topology of side wall functionalization of the (5,5)metallic single-wall carbon nanotube (CNT) with carbenes (>CX(2)) and its effect on electronic properties of the system. It is demonstrated that specific substructures/topology known to stabilize functionalized fullerene molecules can play the same role in CNTs, as well. Upon deepening of functionalization, "uniformity" of addition motives and related continuous changes in properties transform into regular addition patterns with isolated aromatic islands on the nanotube backbone that give rise to jump-like changes in electronic structure.