This article is cited in 37 papers

CONDENSED MATTER

Cluster Dual Fermion Approach to Nonlocal Correlations

H. Hafermann^a, S. Brener^a, A. N. Rubtsov^b, M. I. Katsnel'son^c, A. I. Lichtenstein<sup>a

a</sup> Institute of Theoretical Physics, University of Hamburg, 20355 Hamburg, Germany
^b Department of Physics, Moscow State University
^c Institute for Molecules and Materials, Radboud University, 6525 ED Nijmegen, The Netherlands

Abstract: We formulate a general cluster Dual Fermion Approach to nonlocal correlations in crystals. The scheme allows the treatment of long-range correlations beyond the cluster DMFT and nonlocal effects in realistic calculations of multiorbital systems. We show that the simplest approximation exactly corresponds to the freecluster DMFT. We apply this approach to the one-dimensional Hubbard model. Already the first dual-fermion correction to the free cluster leads to a drastic improvement of the calculated Green function.

PACS: 71.10.Fd, 71.15.-m, 71.27.+a

Received: 13.09.2007
Revised: 18.10.2007

Language: English

 English version: Journal of Experimental and Theoretical Physics Letters, 2007, 86:10, 677–682

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