Berlin 2012 – wissenschaftliches Programm
O 73: Focussed session: Frontiers of electronic structure theory: Strong correlations from first principles V (jointly with TT)
O 73.10: Vortrag
Donnerstag, 29. März 2012, 18:30–18:45, HE 101
Critical properties of the half-filled Hubbard model in three dimensions — •Georg Rohringer1, Alessandro Toschi1, Andrey Katanin2, and Karsten Held1 — 1Institute for Solid State Physics, Vienna University of Technology 1040 Vienna, Austria — 2Institute of Metal Physics, Ekaterinburg, Russia
By means of the dynamical vertex approximation(DΓA)  we include spatial correlations on all length scales beyond the dynamical mean field theory (DMFT) for the half-filled Hubbard model in three dimensions. The most relevant changes due to non-local fluctuations are : (i) a deviation from the mean-field critical behavior with the same critical exponents as for the three dimensional Heisenberg (anti)-ferromagnet and (ii) a sizable reduction of the Néel temperature (TN) by ∼ 30% for the onset of antiferromagnetic order. Finally, we give a quantitative estimate of the deviation of the spectra between DΓA and DMFT in different regions of the phase-diagram.
 A. Toschi, A. Katanin, and K. Held, PRB 75, 045118 (2007).
 G. Rohringer, A. Toschi, A. Katanin, and K. Held, PRL in press [arXiv:1104.1919].