One-electron bands, quantum Monte Carlo, and real superconductors

TL;DR

This paper models doped Fullerenes using a tight-binding and Hubbard Hamiltonian, employing quantum Monte Carlo to study metallic screening and its implications for superconductivity.

Contribution

It introduces a realistic model for doped Fullerenes and applies quantum Monte Carlo to analyze screening and superconductivity effects.

Findings

Efficient metallic screening persists near the Mott transition.

Screening impacts Coulomb pseudopotential and electron-phonon interactions.

Model provides insights into superconductivity in doped Fullerenes.

Abstract

We use the doped Fullerenes as an example of how realistic systems can be described by simple models. Starting from the band structure we set up a tight-binding model that describes the t_{1u} conduction band. Adding correlation terms we arrive at a generalized Hubbard Hamiltonian that we treat using quantum Monte Carlo. To address the problem of superconductivity in the doped Fullerenes, we study the screening of a point charge. We find surprisingly efficient metallic screening even for strong correlations, almost up to the Mott transition, and discuss the implications on superconductivity, in particular the effect of the efficient screening on the Coulomb pseudopotential and the electron-phonon coupling.