Motivated by the unexplored complexity of phases present in the multiorbital Hubbard model, we analyze in this work the behavior of a degenerate two-orbital anisotropic Hubbard model at half-filling where both orbitals have equal bandwidths and one orbital is constrained to be paramagnetic (PM), while the second one is allowed to have an antiferromagnetic (AF) solution. Such a model may be relevant for a large class of correlated materials with competing magnetic states in different orbitals such as the recently discovered Fe-based superconductors. Using a dynamical cluster approximation we observe that unique orbital selective phase transitions appear regardless of the strength of the Ising Hund’s rule coupling $J_z$. Moreover, the PM orbital undergoes a transition from a Fermi liquid (FL) to a Mott insulator through a non-FL phase while the AF orbital shows a transition from a FL to an AF insulator through an AF metallic phase. We discuss the implications of the results in the context of the Fe-based superconductors.

• Received 6 June 2011

DOI:https://doi.org/10.1103/PhysRevB.84.020401