How close is LaOFeAs to Mott transition? A model Hamiltonian calculation within the Gutzwiller approximation*

Using a five-band tight binding model for LaOFeAs we study the role of electron correlations on the low energy electronic structure. The phase boundaries between a metallic state and Mott insulating phases are determined as a function of Coulomb repulsion U and Hund's coupling J for a total number of six d-electrons. For realistic values of U and J LaOFeAs is found to be on the metallic side of the phase boundary. In addition we give a number of spectroscopic signatures that can be used to determine whether the electronic excitations of the metallic state are affected by the vicinity to a Mott transition. These results elucidate the role of strong electron correlations in FeAs-based systems.