Dresden 2011 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 42: SC: Fe-based Superconductors - Fe(Se,Te)

TT 42.3: Talk

Wednesday, March 16, 2011, 19:15–19:30, HSZ 304

57Fe NIS studies of phonon DOS in superconducting FeSe_0.5Te_0.5 single crystals — Gerhard Wortmann¹, •Vadim Ksenofontov², Teuta Gasi², Aleksandr Chumakov³, Vladimir Tsurkan⁴, Joachim Deisenhofer⁴, Alois Loidl⁴, and Claudia Felser² — ¹Department of Physics, University of Paderborn, Paderborn, Germany — ²Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, Mainz, Germany — ³European Synchrotron Radiation Facility, Grenoble, France — ⁴Institute of Physics, University of Augsburg, Augsburg, Germany

FeSe and isostructural FeSe_0.5Te_0.5 could provide valuable information for the understanding of the principal mechanisms of superconductivity (SC) in the novel Fe-based superconductors. Using ⁵⁷Fe nuclear inelastic scattering (NIS) we have measured the phonon-DOS in single-crystalline samples of FeSe_0.5Te_0.5 [1] parallel and perpendicular to the c-axis. A study of the phonon-DOS as function of temperature revealed a very similar temperature dependence as observed in FeSe [2], also no changes of the phonon-DOS above and below T_c = 14.5 K. Together with results of conventional ⁵⁷Fe-Mössbauer studies, we can exclude any phonon softening connected with the observed SC [3]. Based on these results and previous studies of FeSe [2,4], we discuss the role of phonons in the mechanisms for SC in the Fe-based systems.
V. Tsurkan et al., arXiv:1006.4453.
V. Ksenovontov et al., Phys. Rev. B 81, 184510 (2010).
J. Lindén et al., arXiv:1008.1680.
S. Medvedev et al., Nature Mater. 87, 630 (2009).