Erik Koch
Correlations in the doped Fullerides

Fullerides are crystals made from C60 molecules. When they are doped with alkali metals, the valence electrons of the alkalis are transfered into the LUMO of the C60 molecules. By hopping between neighboring molecules these electrons can gain kinetic energy. This hopping is, however, highly correlated since the Coulomb repulsion between electrons on the same C60 molecule is quite strong.
We will discuss:
  1. How the electrons in the conduction band of doped C60 can be described by a Hubbard Hamiltonian
  2. How the ground-state energy for such a model Hamiltonian is calculated (we use the fixed-node method described in the lecture by Giovanni Bachelet)
  3. How the Mott transition in the Fullerides is influenced by the degeneracy of the LUMO and the lattice structure
  4. How a test charge on a molecule is screened by the conduction electrons and what implication this has for superconductivity

Last modified: Wed Jun 17 17:30:06 EDT 1998