Synthesis and electronic properties of coalesced graphitic nanocones

Thermal annealing of graphitic conical nanofibers, produced by pyrolysing Pd precursors under an Ar atmosphere at 850–1000 °C, results in the coalescence of adjacent cones. These novel cone-like arrangements exhibit heptagonal and pentagonal carbon rings located in the cauterized rims between adjacent cones. We propose molecular models that resemble such structures and calculate their electronic properties using a self-consistent local approach based on a realistic tight-binding Hamiltonian. The calculations demonstrate that coalesced cones exhibit a conducting behaviour and a local analysis of the density of states (DOS) reveals that curvature is crucial in modifying the electronic structure.