Fate of the false Mott-Hubbard transition in two dimensions
  We have studied the impact of non-local electronic correlations at all length scales on the Mott-Hubbard metal-insulator transition in the unfrustrated two-dimensional Hubbard model. Combining dynamical vertex approximation, lattice quantum Monte-Carlo and variational cluster approximation, we demonstrate that scattering at long-range fluctuations, i.e., Slater-like paramagnons, opens a spectral gap at weak-to-intermediate coupling -- irrespectively of the preformation of localized or short-ranged magnetic moments. This is the reason, why the two-dimensional Hubbard model is insulating at low enough temperatures for any (finite) interaction and no Mott-Hubbard transition is observed. 
T. Sch\"afer, F. Geles, D. Rost, G. Rohringer, E. Arrigoni, K. Held,   N. Bl\"umer, M. Aichhorn, A. Toschi
cond-mat.str-el