Abstract
We study the static screening in a Hubbard-like model using quantum Monte Carlo methods. We find that the random phase approximation is surprisingly accurate almost up to the Mott transition. We argue that in alkali-doped fullerenes the Coulomb pseudopotential is not very much reduced by retardation effects. Therefore efficient screening is important in reducing sufficiently to allow for an electron-phonon driven superconductivity. In this way the fullerides differ from the conventional picture, where retardation effects play a major role in reducing the electron-electron repulsion.
- Received 17 February 1999
DOI:https://doi.org/10.1103/PhysRevLett.83.620
©1999 American Physical Society