Screening and Non-local Correlations in the Extended Hubbard Model from Self-Consistent Combined GW and Dynamical Mean Field Theory

Abstract

We describe a recent implementation of the combined GW and dynamical mean field (DMFT) method "GW+DMFT" for the two-dimensional Hubbard model with on-site 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 self-consistent solution of the GW+DMFT equations, namely the hybridization expansion continuous-time algorithm for solving the dynamical impurity model that arises within the GW+DMFT scheme. We compute the low-temperature phase diagram of the extended Hubbard model, addressing the metal-insulator transition at small intersite interactions and the transition to a charge-ordered state for stronger intersite repulsions. 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 by extracting a charateristic plasma frequency and show how it affects the local spectral function.

23 pages, 14 figures

References in corpus (11)

• Quasiparticle self-consistent $GW$ method; a basis for the independent-particle approximation
• Dynamical vertex approximation - a step beyond dynamical mean field theory
• Hubbard U and Hund's Exchange J in Transition Metal Oxides: Screening vs. Localization Trends from Constrained Random Phase Approximation
• Screened Coulomb interaction in the maximally localized Wannier basis
• Efficient DMFT-simulation of the Holstein-Hubbard Model
• The f-electron challenge: localized and itinerant states in lanthanide oxides united by GW@LDA+U
• Combined GW and dynamical mean field theory: Dynamical screening effects in transition metal oxides
• Spectral Properties of Correlated Materials: Local Vertex and Non-Local Two-Particle Correlations from Combined GW and Dynamical Mean Field Theory
• Two-stage metal-insulator transition in the 2D Hubbard model: momentum selectivity in the 8-site dynamical cluster approximation
• Effective Onsite Interaction for Dynamical Mean-Field Theory
• Non-Perturbative Treatment of Charge and Spin Fluctuations in the Two-Dimensional Extended Hubbard Model: Extended Two-Particle Self-Consistent Approach