Cooperative Jahn-Teller effect and the band structures of KxC60 crystals

Band reconstructions upon doping are studied with the use of a generalized version of the Su-Shrieffer-Heeger model for the intermolecular and intramolecular degrees of freedom. A simple model describing the covalent bond formation in C60 compounds is proposed. Electron charge distributions over the molecular surface and Jahn-Teller distortions of carbon atoms in C60 are calculated self-consistently for linear C60 polymer and C60− polyanion chains. It is shown that the polymerization of equally oriented C60 molecules under phase transitions may be caused by the cooperative Jahn-Teller effect.