Dresden 2009 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 40: Superconductivity: Ferropnictides 1

TT 40.10: Talk

Thursday, March 26, 2009, 16:30–16:45, HSZ 03

Observation of the many body satellite in Ba_1−xK_xFe₂As₂ single crystals by resonant x-ray photoemission spectroscopy — Andreas Koitzsch¹, Thomas Kroll¹, Roberto Kraus¹, Martin Knupfer¹, Bernd Büchner¹, David Batchelor², Guoli Sun³, Dunlu Sun³, and •Chengtian Lin³ — ¹IFW Dresden, Postfach 270116, 01171 Dresden — ²Forschungszentrum Karlsruhe, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen — ³Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, 70569 Stuttgart

Valence band and core level measurements of Ba_1−xK_xFe₂As₂ single crystals with photon energies across the Fe L₃ absorption edge are reported. Within the resonance regime of the photon energy profile an intensity enhancement centered at E = 3.6 eV is observed which can be identified as the many body satellite. The energy position of the satellite matches the expectations based on previously extracted parameters from Fe L x-ray absorption spectroscopy and Fe 2p x-ray photoemission spectroscopy. The results show, that the Hubbard repulsion U, although smaller than the bandwidth, preserves a clear physical meaning giving rise to local electron phenomena in an otherwise itinerant environment.