Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 2: Focussed session: Frontiers of electronic structure theory: Strong correlations from first principles I (jointly with TT)
O 2.9: Talk
Monday, March 26, 2012, 13:00–13:15, HE 101
GW+EDMFT simulation of the U-V Hubbard model — •Thomas Ayral1, Silke Biermann2, and Philipp Werner1 — 1Theoretische Physik, ETH Zurich, 8093 Zürich, Switzerland — 2Centre de Physique Théorique, Ecole Polytechnique, CNRS-UMR7644, 91128 Palaiseau, France
We study the extended Hubbard model with on-site and nearest-neighbor repulsion on a square lattice within a GW+EDMFT scheme at finite temperature and half-filling. This technique combines the successful description of screening effects due to non-local interactions within Hedin's GW approximation with the dynamical mean field description of strong local interactions. We analyze the role of the frequency-dependence of the local interactions in the formation of the charge-ordered phase and show that non-local contributions to the self-energies generated via the GW approximation have a substantial impact on the local observables and on the phase diagram, depending on the interaction parameters. Our work thus has implications for electronic structure techniques based on Hedin's GW approximation in that it demonstrates a local many-body vertex to be sufficient for fully self-consistent GW calculations.