Regensburg 2019 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 5: Superconductivity: Fe-based Superconductors - FeSe and 122

TT 5.12: Vortrag

Montag, 1. April 2019, 12:30–12:45, H23

Charge density wave instability in Ba(Ni_1−xFe_x)₂As₂ probed by time-resolved optical spectroscopy. — •V. Yu. Grigorev^1,2, 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 T_c of 24 K [1]. In its structural homologue BaNi₂As₂, however, superconductivity is observed even in undoped samples, yet the maximal T_c 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 BaNi_1.93Fe_0.07As₂, 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.
J. Paglione and R. L. Greene, Nat. Phys. 6, 645 (2010)
Z. G. Chen et al., Phys. Rev. B 80, 094506 (2009)
S. Lee et al., arXiv:1801.04874
H. Schäfer et al., Phys. Rev. B. 89, 045106 (2014)