Dresden 2011 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 36: SC: Fe-based Superconductors - 122 - Properties, Electronic Structure, Mechanisms

TT 36.11: Talk

Wednesday, March 16, 2011, 16:45–17:00, HSZ 304

Electronic dispersion anomalies in iron-pnictide superconductors — •Andreas Heimes¹, Roland Grein², and Matthias Eschrig¹ — ¹Department of Physics, Royal Holloway, University of London — ²Institut für Theoretische Festkörperphysik, Karlsruhe Institut of Technology

Recently, experimental studies of the spin excitation spectrum revealed a strong temperature dependence in the normal state and a resonance feature in the superconducting state of several Fe-based superconductors. Based on these findings, we develop a model of electrons interacting with a temperature dependent magnetic excitation spectrum and apply it to angle resolved photoemission in Ba_1−x K_x Fe₂ As₂. We reproduce in quantitative agreement with experiment a renormalization of the quasiparticle dispersion both in the normal and the superconducting state, and the dependence of the quasiparticle linewidth on binding energy. We estimate the strength of the coupling between electronic and spin excitations. Our findings support a dominantly magnetic pairing mechanism.