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arXiv:cond-mat/9803295 · Physical review. B, Condensed matter

Nonlocal dynamical correlations of strongly interacting electron systems

Matthias H. Hettler, A. N. Tahvildar-Zadeh, Mark Jarrell, Thomas Pruschke, H. R. Krishnamurthy

Published Sep 15, 1998• 511 citations
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Abstract

We introduce an extension of the dynamical mean-field approximation (DMFA) that retains the causal properties and generality of the DMFA, but allows for systematic inclusion of nonlocal corrections. Our technique maps the problem to a self-consistently embedded cluster. The DMFA (exact result) is recovered as the cluster size goes to 1 (infinity). As a demonstration, we study the Falicov-Kimball model using a variety of cluster sizes. We show that the sum rules are preserved, the spectra are positive definite, and the nonlocal correlations suppress the charge-density wave transition temperature.

DOI
10.1103/physrevb.58.r7475

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