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TT: Tiefe Temperaturen

TT 28: Correlated Electrons: General Theory

TT 28.9: Vortrag

Donnerstag, 30. März 2006, 12:15–12:30, HSZ 301

Non-local corrections to DMFT: magnetic correlation effects on the spectral function — •Alessandro Toschi, Andrey Katanin, and Karsten Held — Max-Planck Institut für Festkörperforschung, Heisenbergstr. 1,*D-70569 Stuttgart, Germany

We consider non-local corrections to the dynamical mean-field theory (DMFT) self-energy and spectral functions in the presence of strong magnetic fluctuations. Specifically, we evaluate the momentum-dependent self-energy starting from the one- and two-particle DMFT Green functions. Contrary to previous studies (e.g., the GW+DMFT approach) the local three-frequency vertex corrections are taken into account. Unlike the dynamical cluster approximation or the cellular DMFT approach, our method allows to study the effect of magnetic fluctuations with large correlation length. The effect of antiferromagnetic fluctuations is studied for the single-band Hubbard model at half filling. Going beyond DMFT we find precursor effects of the antiferromagnetic order already in the paramagnetic phase: the momentum dependence of the self-energy becomes particularly strong in the vicinity of the antiferromagnetic transition.