Extension of dynamical mean-field theory by inclusion of nonlocal two-site correlations with variable distance

Abstract

We present a novel approximation scheme for the treatment of strongly correlated electrons in arbitrary crystal lattices. The approach extends the well-known dynamical mean field theory to include nonlocal two-site correlations of arbitrary spatial extent. We extract the nonlocal correlation functions from two-impurity Anderson models where the impurity-impurity distance defines the spatial extent of the correlations included. Translational invariance is fully respected by our approach since correlation functions of any two-impurity cluster are periodically embedded to $k$-space via a Fourier transform. As a first application, we study the two-dimensional Hubbard model on a simple-cubic lattice. We demonstrate how pseudogap formation in the many-body resonance at the Fermi level results from the inclusion of nonlocal correlations.

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Cited by in corpus (5)

• Practical consequences of Luttinger-Ward functional multivaluedness for cluster DMFT methods
• Effective low-energy description of the two impurity Anderson model: RKKY interaction and quantum criticality
• Dynamical Mean Field Approximation Applied to Quantum Field Theory
• Realistic quantum critical point in one-dimensional two-impurity models
• Fine structure of the spectra of the Kondo lattice model: two-site cellular DMFT study