Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 31: Superconductivity: Fe-based Superconductors – 122 and 111

TT 31.11: Talk

Tuesday, March 17, 2015, 12:30–12:45, H 2053

Persistence of high-energy spin fluctuations in electron doped NaFeAs — •Jonathan Pelliciari¹, Yaobo Huang^{1, 2}, Marcus Dantz¹, Valentina Bisogni¹, Paul Olalde Velasco¹, Changqing Jin², and Thorsten Schmitt¹ — ¹Paul Scherrer Institute, Villigen, Switzerland — ²Institute of Physics Chinese Academy of Sciences, Beijing, China

Resonant Inelastic X-ray Scattering (RIXS) is a powerful method for probing spin fluctuations in cuprate and iron pnictide superconductors [1, 2]. We present a high resolution Fe L₃ RIXS study of parent and superconducting NaFe_1−xCo_xAs. Spectral shape decomposition reveals the persistence of broad dispersive magnetic excitations for all doping levels. In contrast to previous RIXS experiments on hole-doped Ba_1−xK_xFe₂As₂ compounds [1], the energy of such modes is not affected by doping. The magnetic weight per iron atom of such magnons and paramagnons remains constant. However, renormalized per formula unit the magnetic weight decreases with doping. We argue that cobalt-doping is mainly tuning the electronic correlations without affecting the dispersion range of the magnetic excitations, only reducing their intensity.

[1] K. J. Zhou et al, Nat. Comm., 4, 1470 (2013)

[2. M. P. M. Dean et al, Nature Materials 12, 1019 (2013)