Laboratoire de Physique Théorique
Toulouse - UMR 5152

In this talk, a brief introduction to experimental and theoretical results for the iron pnictides will be given, trying to compare its similarities and differences with the cuprates. The pnctides parent compound, in all the families of superconducting pnictides known, is a semimetal with an Spin Density Wave (SDW) ground state, which under doping, for some families, and under pressure for others, becomes superconducting (max T_c 55 K). The model of choice has been a 5-band Hubbard model, with longer than nearest-neighbor tight binding hoppings and several on-site correlation terms. An RPA solution to this model will be presented for the dynamic spin susceptibility and also for the pairing function (time permiting). It will be argued that the extreme richness of the Fermi surface (coming from all the hybridize d-states) results in RPA solutions which are very dependent on the tight binding hopping terms. This may be one of the important difference in relation to the cuprates.