Details

Autor(en) / Beteiligte

• Jabben, Torben
• Grewe, Norbert
• Schmitt, Sebastian

Titel

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

Ist Teil von

• Physical review. B, Condensed matter and materials physics, 2012-04, Vol.85 (16), Article 165122

Erscheinungsjahr

2012

Quelle

American Physical Society [PROLA]

Beschreibungen/Notizen

• We present an 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. A comparison of the spectral function with the dynamical-cluster approximation shows qualitative agreement of high- as well as low-energy features.