Electronic structure of Li-doped polyparaphenylene

Abstract

Electron-energy-loss spectroscopy has been used to investigate the electronic structure of Li-doped polyparaphenylene. For low doping concentration the results are consistent with the bipolaron model showing two defect states in the gap. At the highest doping level, the gap between bonding and antibonding $\ensuremath{\pi}$ electrons is closed and a metallic state is observed.