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TT: Fachverband Tiefe Temperaturen

TT 13: Superconductivity: Fe-based Superconductors - 122

TT 13.1: Vortrag

Montag, 20. März 2017, 15:00–15:15, HSZ 103

Fermi surface and effective masses in photoemission response of the K doped BaFe₂As₂ superconductor — Gerald Derondeau¹, Federico Bisti², Jürgen Braun¹, Hubert Ebert¹, Vladimir Strocov², and •Jan Minar^1,3 — ¹LMU München, Germany — ²Swiss Light Source, PSI, Villigen, Switzerland — ³University of West Bohemia, Pilsen, Czech Republic

The angle-resolved photoemission spectra of the K doped superconductor BaFe₂As₂ have been investigated both experimentally and theoretically. Our results explain the previously obscured origins of all salient features of the ARPES response of this paradigm pnictide compound and reveal the origin of the Lifshitz transition. Comparison of calculated ARPES spectra with the underlying DMFT band structure shows an important impact of final state effects, which results for three-dimensional states in a deviation of the ARPES spectra from the underlying spectral function. In particular, the apparent effective mass enhancement seen in the ARPES response is not an entirely intrinsic property of the quasiparticle valence bands but has a significant extrinsic contribution from the photoemission process and thus differ from its true value. Because this effect is more pronounced for low photoexcitation energies, soft-X-ray ARPES delivers more accurate values of the mass enhancement due to a sharp definition of the 3D electron momentum.