Berlin 2015 – wissenschaftliches Programm
TT 21.24: Poster
Montag, 16. März 2015, 15:00–18:00, Poster B
Superconductivity from Magnetic Fluctuations in FeTe1−xSex-Feedback of Double Stripe Magnetism on Itinerant Spin Excitations — •Masoud Mardani1, Johannes knolle2, Ilya Eremin3, and Roderich Moessner1 — 1Max Planck Institute for the Physics of Complex Systems, D-01187 Dresden, Germany — 2TCM Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom — 3Institute for Theoretical Physics III, Ruhr-Universität Bochum, D-44801 Bochum, Germany
Iron-chalcogenide superconductors exhibit an unusual double stripe antiferromagnetic parent phase with ordering vector QAF = (π/2,π/2) (in the one iron unit cell). In addition, magnetic excitations in optimally doped systems are peaked at momenta QSF = (π,0)/(0,π), which is in contrast to most other families of iron-based superconductors. There, both the magnetic order of the parent compounds and the magnetic fluctuations in the superconducting state have the same momentum QSF, which is taken as a strong argument in favor of spin-fluctuation induced superconductivity. Here, we model iron-chalcogenides as a system of itinerant electrons coupled to localized electrons responsible for the double stripe magnetism. We study the feedback of this unusual magnetic order on the itinerant spin excitations at QSF and show that they increase with decreasing magnetism. We make connection to recent INS experiments and reproduce qualitatively the behavior of magnetic excitations in FeTe1−xSex from x=0 towards x=0.4.