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TT: Fachverband Tiefe Temperaturen

TT 10: Poster Session: Superconductivity

TT 10.18: Poster

Monday, March 14, 2011, 14:00–18:00, P4

Magnetic and orbital order in a spin-fermion model for pnictides — •Thomas Prestel and Maria Daghofer — Institute for Theoretical Solid State Physics, IFW Dresden, 01171 Dresden, Germany

We study a spin-fermion model for iron pnictides [1] that couples itinerant electrons in the xz and yz orbitals to a local spin degree of freedom, which is modelled as a classical spin.We use classical Monte Carlo simulation as well as Exact diagonalization technique to investigate this model. At half filling, corresponding to undoped compounds, we find Flux-phase magnetic ordering rather than the experimentally observe C-type ordering, while slight doping as well as a magnetic single-ion anisotropoy stabillize the observed magnetic phase. We study this phase competition. We also study the model supplemented by local impurities and find the impurities to have a small impact on the orbital occupation of surrounding sites.
W.-G. Yin, C.-C. Lee, W. Ku, PRL 105, 107004 (2010)