Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 5: Superconductivity: Fe-based Superconductors - FeSe and 122
TT 5.12: Talk
Monday, April 1, 2019, 12:30–12:45, H23
Charge density wave instability in Ba(Ni1−xFex)2As2 probed by time-resolved optical spectroscopy. — •V. Yu. Grigorev1,2, A. Mejas3, T. Dong1, Th. Wolf4, A. A. Haghighirad4, C. Meingast4, M. Le Tacon4, M. Merz4, and J. Demsar1 — 1Institute of Physics, Johannes Gutenberg-University Mainz, Mainz, Germany — 2Graduate School of Excellence, Materials Science in Mainz (MAINZ), Mainz, Germany — 3Institute for solid state physics, TU Wien, Vienna, Austria — 4Institute for Solid State Physics, KIT, Karlsruhe, Germany
In Fe-based superconductor BaFe2As2, which displays the spin-density wave order, superconductivity is induced by chemical doping, reaching the maximum Tc of 24 K [1]. In its structural homologue BaNi2As2, however, superconductivity is observed even in undoped samples, yet the maximal Tc in Co-doped samples does not exceed 3 K [2,3]. Recent diffraction studies [4] suggest that superconductivity in BaNi2As2 is competing with the unidirectional charge-density-wave (CDW) order. Here we report on optical femtosecond time-resolved spectroscopy on weakly doped BaNi1.93Fe0.07As2, aiming at investigating the CDW collective modes - see e.g. [4]. We present a clear evidence for a commensurate-to-incommensurate CDW lock-in phase transition at 45 K, and the low temperature amplitude mode at 1 THz in the commensurate CDW phase.
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