Ab initio many-body treatment of the electronic structure of metals

Abstract

We propose a method for an ab initio determination of the second-quantized Hamiltonian describing the electronic properties of a certain material. A standard band structure calculation yields the Bloch functions, from which the static susceptibility and dielectric function can be calculated within the random phase approximation and maximally localized Wannier functions can be obtained. Within this Wannier basis all relevant one-particle and screened Coulomb matrix elements are calculated. This yields a multi-band Hubbard Hamiltonian with ab initio parameters to which established methods of many-body theory can be applied. For the simple metal Li an extended, four-band Hubbard model is obtained and a weak-coupling approximation for the self energy is justified.