Evidence for an Alkalilike Conduction Band in Alkali Graphite Intercalation Compounds

The valence bands of pure graphite and several alkali graphite intercalation compounds were studied by ultraviolet photoelectron spectroscopy ($h\nu =21.2\mathrm{}$ eV). The most significant observation is an intensity peak at the Fermi energy $E_{\mathrm{F}}$ in the intercalation compounds. This peak is mainly due to alkalilike $s$ states. The density of states at $E_{\mathrm{F}}$ is enhanced by a factor of 30 compared with pure graphite. The alkalilike conduction bands in the first stage alkali graphite interclation compounds are similar to those of pure alkali metals.