Realistic investigations of correlated electron systems with LDA + DMFT

• Published in: Physica Status Solidi (b) 2006-09, Vol.243 (11), p.2599-2631
• Main Authors: Held, K., Nekrasov, I. A., Keller, G., Eyert, V., Blümer, N., McMahan, A. K., Scalettar, R. T., Pruschke, Th, Anisimov, V. I., Vollhardt, D.
• Format: Article
• Language: English
• Subjects: 71.10.-w; 71.15.-m; 71.15.Mb; 71.27.+a; 71.30.+h
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.200642053

Conventional band structure calculations in the local density approximation (LDA) [1–3] are highly successful for many materials, but miss important aspects of the physics and energetics of strongly correlated electron systems, such as transition metal oxides and f‐electron systems displaying, e.g., Mott insulating and heavy quasiparticle behavior. In this respect, the LDA + DMFT approach which merges LDA with a modern many‐body approach, the dynamical mean‐field theory (DMFT), has proved to be a breakthrough for the realistic modeling of correlated materials. Depending on the strength of the electronic correlation, a LDA + DMFT calculation yields the weakly correlated LDA results, a strongly correlated metal, or a Mott insulator. In this paper, the basic ideas and the set‐up of the LDA + DMFT(X) approach, where X is the method used to solve the DMFT equations, are discussed. Results obtained with X = QMC (quantum Monte Carlo) and X = NCA (non‐crossing approximation) are presented and compared, showing that the method X matters quantitatively. We also discuss LDA + DMFT results for two prime examples of correlated materials, i.e., V2O3 and Ce which undergo a Mott–Hubbard metal–insulator and volume collapse transition, respectively. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)