Journal article

Influence of Fock exchange in combined many-body perturbation and dynamical mean field theory

  • Ayral, Thomas Institut de Physique Théorique (IPhT), CEA, CNRS, Gif-sur-Yvette, France - Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey, USA
  • Biermann, Silke Centre de Physique Théorique, Ecole Polytechnique, CNRS, Université Paris Saclay, Palaiseau, France
  • Werner, Philipp Department of Physics, University of Fribourg, Switzerland
  • Boehnke, Lewin Department of Physics, University of Fribourg, Switzerland
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Published in:
  • Physical Review B. - 2017, vol. 95, no. 24, p. 245130
English In electronic systems with long-range Coulomb interaction, the nonlocal Fock- exchange term has a band-widening effect. While this effect is included in combined many-body perturbation theory and dynamical mean field theory (DMFT) schemes, it is not taken into account in standard extended DMFT (EDMFT) calculations. Here, we include this instantaneous term in both approaches and investigate its effect on the phase diagram and dynamically screened interaction. We show that the largest deviations between previously presented EDMFT and GW+EDMFT results originate from the nonlocal Fock term, and that the quantitative differences are especially large in the strong-coupling limit. Furthermore, we show that the charge-ordering phase diagram obtained in GW+EDMFT methods for moderate interaction values is very similar to the one predicted by dual-boson methods that include the fermion-boson or four-point vertex.
Faculté des sciences et de médecine
Département de Physique
  • English
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