Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 75: Ultrafast Electron and Spin Dynamics
O 75.3: Vortrag
Mittwoch, 22. März 2017, 15:30–15:45, TRE Phy
Ultrafast dynamics in Fe-pnictides analyzed by femtosecond time-resolved x-ray spectroscopy — •Andrea Eschenlohr1, Mohammadmahdi Afshari1, Klaus Sokolowski-Tinten1, Niko Pontius2, Hidenori Hiramatsu3, Hideo Hosono3, Jörg Fink4, and Uwe Bovensiepen1 — 1Univ. Duisburg-Essen — 2Helmholtz Zentrum Berlin — 3Tokyo Institute of Technology — 4IFW Dresden
The electronic properties of Fe-pnictide high temperature superconductors are strongly influenced by the Fe-As distance, which is linked to the superconducting critical temperature [1] and can be modified not only through doping and external pressure, but also transiently by the coherent A1g phonon mode [2]. Element- and orbital-specific x-ray absorption spectroscopy (XAS) provides information on the local electronic structure. By employing femtosecond (fs) x-ray pulses from the BESSY II Femtoslicing source, we perform fs time-resolved XAS of BaFe2(AsP)2. We observe pump-induced changes at the Fe L3 edge that are described by the interplay of a transient decrease in absorption, shift in binding energy and peak broadening. This complex behavior will be discussed in the context of electronic and phononic excitations in the Fe-pnictides, in particular photodoping and related changes of the transient chemical potential [3].
We acknowledge funding by the DFG through SPP 1458 and Sfb 1242, and the BMBF through FEMTOSPEX.
[1] Mizuguchi et al., Supercond. Sci. Technol. 23, 054013 (2010). [2] Rettig et al., PRL 114, 067402 (2015); Gerber et al., Nat. Commun. 6, 7377 (2015). [3] Yang et al., PRL 112, 207001 (2014).