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TT: Fachverband Tiefe Temperaturen

TT 13: Superconductivity: Fe-based Superconductors - 122

TT 13.5: Vortrag

Montag, 20. März 2017, 16:00–16:15, HSZ 103

Superconductivity induced changes of phonon lifetime in Ba(Fe_0.94Co_0.06 )₂As₂ — •Maximilian Kauth¹, Frank Weber¹, Thomas Wolf¹, and Thomas Keller² — ¹Institut für Festkörperphysik, Karlsruher Institut für Technologie — ²Max-Planck-Institut für Festkörperforschung, Stuttgart

We have investigated the life time of the transversal acoustic (TA) phonon mode in the Fe-based high-temperature superconductor Ba(Fe_0.94Co_0.06)₂As₂ along the [100] direction. We used the neutron resonant spin echo (NRSE) technique at the TRISP spectrometer at the Heinz Maier-Leibnitz Zentrum [1]. This phonon mode is the soft mode of the structural phase transition present in lower doped samples. Recent measurements showed evidence that it is sensitive to nematic fluctuations in this compound [2]. We observe a clear maximum of the TA phonon linewidth at the superconducting transition temperature T_C ≈ 24 K. This is the first experimental evidence of changes of the phonon lifetime in Fe-based superconductors.

[1] MPI für Festkörperforschung et al., Journal of large-scale research facilities, 1, A37 (2015).

[2] F. Weber et al., arXiv:1610.00099 (2016)