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Screening and nonlocal correlations in the extended Hubbard model from self-consistent combined GW and dynamical mean field theory

  • Ayral, Thomas Theoretische Physik, ETH Zurich, Switzerland - Centre de Physique Théorique, Ecole Polytechnique, Palaiseau, France - Institut de Physique Théorique (IPhT), Gif-sur-Yvette, France
  • Biermann, Silke Centre de Physique Théorique, Ecole Polytechnique, Palaiseau, France - Japan Science and Technology Agency, Kawaguchi, Japan
  • Werner, Philipp Theoretische Physik, ETH Zurich, Switzerland - Department of Physics, University of Fribourg, Switzerland
    29.03.2013
Published in:
  • Physical Review B. - 2013, vol. 87, no. 12, p. 125149
English We describe a recent implementation of the combined GW and dynamical mean field method (GW+DMFT) for the two-dimensional Hubbard model with onsite and nearest-neighbor repulsion. We clarify the relation of the GW+DMFT scheme to alternative approaches in the literature, and discuss the corresponding approximations to the free-energy functional of the model. Furthermore, we describe a numerically exact technique for the solution of the GW+DMFT equations, namely, the hybridization expansion continuous-time algorithm for impurity models with retarded interactions. We compute the low-temperature phase diagram of the half-filled extended Hubbard model, addressing the metal-insulator transition at small intersite interactions and the transition to a charge-ordered state for stronger intersite repulsions. GW+DMFT introduces a nontrivial momentum dependence into the many-body self-energy and polarization. We find that the charge fluctuations included in the present approach have a larger impact on the latter than on the former. Finally, within the GW+DMFT framework, as in extended DMFT, the intersite repulsion translates into a frequency dependence of the local effective interaction. We analyze this dependence and show how it affects the local spectral function.
Faculty
Faculté des sciences et de médecine
Department
Département de Physique
Language
  • English
Classification
Physics
License
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Persistent URL
https://folia.unifr.ch/unifr/documents/303008
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