Berlin 2018 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 35: Superconductivity: Fe-based Superconductors - 122 and Theory

TT 35.2: Talk

Tuesday, March 13, 2018, 09:45–10:00, A 053

Superconductivity induced changes of the phonon lifetime in Ba(Fe_0.94Co_0.06 )₂As₂ — •Maximilian Kauth¹, Frank Weber¹, John-Paul Castellan¹, Thomas Wolf¹, Thomas Keller², and Dimitry Reznik³ — ¹Institute for Solid State Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany — ²Max-Planck-Institute for Sodid State Research, Stuttgart, Germany — ³Department of Physics, University of Colorado atBoulder, Boulder, Colorado, 80309, USA

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 thermal neutron triple axis spectrometer (TAS) 1T at LLB at CEA Saclay and the neutron resonant spin echo (NRSE) technique at the TRISP spectrometer at the MLZ in Garching [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 with both measurement techniques (regular TAS and NRSE). This is the first experimental evidence of changes of the phonon lifetime in Fe-based superconductors.
MPI for Solid State Research et al., Journal of large-scale research facilities, 1, A37 (2015).
F. Weber et al., arXiv:1610.00099 (2016).