Theoretical study on electronic states of potassium-oxygen-graphite ternary intercalation compounds

Abstract

The electronic states of stage-1 and -2 potassium-oxygen-graphite ternary intercalation compounds are studied from first principles by constructing several simple structural models. For all models, the graphite π* band and the oxygen 2p band form the electron and hole Fermi surfaces, respectively. Oxygen 2p bands with small dispersion contribute to the large density of states near the Fermi level. The whole 4s charge of potassium is transferred to oxygen and carbon, and the present compounds are classified into the donor type. Furthermore, no magnetic moment appears on oxygen irrespective of its arrangement, for which the reason is discussed.