Antiferromagnetism in the 2D Hubbard model: phase transition and local   quantities
  We present a first study of the antiferromagnetic state in the 2D t-t'-U model at finite temperatures by the composite operator method, providing simultaneously a fully self-consistent treatment of the paramagnetic and the AF phase. Near half-filling the critical value of the Coulomb repulsion as a function of t' and the temperature dependence of the magnetization and of the internal energy per site have been studied. 
Roland Muenzner, Adolfo Avella, Ferdinando Mancini (University of   Salerno, Italy)