Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 17: Superconductivity: Fe-based Superconductors - 122 Part 2 & Theory
TT 17.6: Vortrag
Dienstag, 27. März 2012, 11:00–11:15, H 2053
Spectral density in a nematic state of a three-orbital model for iron pnictides — •Maria Daghofer1, Andrew Nicholson2, and Adriana Moreo2 — 1IFW Dresden, Germany — 2University of Tennessee and Oak Ridge National Laboratory, TN, USA
We study a nematic phase, i.e., broken rotational symmetry without long-range magnetic order, for a three-orbital model describing the dominant orbitals and bands around the Fermi surface of pnictide superconductors. Using cluster-perturbation theory, we calculate the spectral density A(k,ω) for the case of very short-range magnetic order that chooses the ordering vector (π,0) over the equivalent (0,π) and thus breaks the fourfold lattice symmetry. The resulting asymmetry between the xz band at Y=(0,π) and the yz band X=(π,0) is in very good agreement with angle-resolved photo-emission spectroscopy: The yz bands at X moves to higher energies. We also discuss the impact of onsite Coulomb repulsion and orbital polarization.