Many-body perturbation theory using the density-functional concept: beyond the GW approximation.
We propose an alternative formulation of many-body perturbation theory that uses the density-functional concept. Instead of the usual four-point integral equation for the polarizability, we obtain a two-point one, which leads to excellent optical absorption and energy-loss spectra. The corresponding three-point vertex function and self-energy are then simply calculated via an integration, for any level of approximation. Moreover, we show the direct impact of this formulation on the time-dependent density-functional theory. Numerical results for the band gap of bulk silicon and solid argon illustrate corrections beyond the GW approximation for the self-energy.
Bruneval
Fabien
F
Laboratoire des Solides Irradiés, UMR 7642 CNRS/CEA, Ecole Polytechnique, 91128 Palaiseau, France.
Sottile
Francesco
F
Olevano
Valerio
V
Del Sole
Rodolfo
R
Reining
Lucia
L