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We study the phase transition in Cu-substituted iron-based superconductors with a new developed real-space Greens function method. We find that Cu substitution has strong effect on the orbital-selective Mott transition introduced by the Hunds rule coupling. The redistribution of the orbital occupancy which is caused by the increase of the Hunds rule coupling, gives rise to the Mott-Hubbard metal-insulator transition in the half-filled $d_{xy}$ orbital. We also find that more and more electronic states appear inside that Mott gap of the $d_{xy}$ orbital with the increase of Cu substitution, and the in-gap states around the Fermi level are strongly localized at some specific lattice sites. Further, a distinctive phase diagram, obtained for the Cu-substituted Fe-based superconductors, displays an orbital-selective insulating phase, as a result of the cooperative effect of the Hunds rule coupling and the impurity-induced disorder.
Iron-based superconductors display a variety of magnetic phases originating in the competition between electronic, orbital, and spin degrees of freedom. Previous theoretical investigations of the multi-orbital Hubbard model in one dimension revealed
We report a quantum phase transition between orbital-selective Mott states, with different localized orbitals, in a Hunds metals model. Using the density matrix renormalization group, the phase diagram is constructed varying the electronic density an
The twin issues of the nature of the normal state and competing order(s) in the iron arsenides are central to understanding their unconventional, high-Tc superconductivity. We use a combination of transport anisotropy measurements on detwinned Sr(Fe(
We study non-local correlations in a three-orbital Hubbard model defined on an extended one-dimensional chain using determinant quantum Monte Carlo and density matrix renormalization group methods. We focus on a parameter with robust Hunds coupling,
The heavy fermion state with Kondo-hybridization (KH), usually manifested in f-electron systems with lanthanide or actinide elements, was recently discovered in several 3d transition metal compounds without f-electrons. However, KH has not yet been o