Jahn-Teller effect and electron correlation in alkali doped fullendes

Abstract

The interplay between Jahn-Teller effect and electron correlation in alkali doped fullerides is reviewed for compounds from both sides of Mott-Hubbard transition. In Mott-Hubbard fullerides the nature of low-lying excitations strongly depends on the symmetry of the compounds, corresponding either to spin (Heisenberg) type for low symmetry compounds (K3(NH 3)C60) or to spin-vibronic superexchange for cubic compounds (Li3(NH3)6C60). In the band fullerides (A3C60, A4C60, A = K, Rb) the Jahn-Teller effect leads to a splitting of the cubic band structure in three or two unequally populated subbands (orbital disproportionation), which gives rise to a number of features in the spectroscopy of these compounds. © 2005 WILEY-VCH Verlas GmbH & Co. KGaA. Weinheim.