Prediction of Electronic Interlayer States in Graphite and Reinterpretation of Alkali Bands in Graphite Intercalation Compounds

The existence of a new kind of electron state in graphite and in alkali graphite intercalation compounds is predicted with use of self-consistent local-density all-electron theory. These interlayer states, which exhibit free-electron character parallel to the layers, form a band close to the Fermi energy and provide for alkali graphite intercalation compounds a new understanding of the origin of bands previously interpreted incorrectly as arising from alkali s electrons.