Electronic Properties of Linear C60 Polyanions

The electronic structure of a linear fullerene polymer anion is calculated based on the optimized geometry of a fullerene trimer. The band structure exhibits both non-dispersive and dispersive bands, indicating a mixture of localized and extended states. Two independent methods both show that the states at the Fermi energy are localized. However, there is a very narrow gap, of the order of 0.2-0.3 eV, to a dispersive unoccupied band. Taking the effects of counterions and surrounding chains into account, this gap can reduce to a pseudogap, or even disappear, which would allow for low-lying extended states and essentially metallic behaviour.