%0 Journal Article
%A Yang, L. X.
%A Rohde, G.
%A Chen, Y. J.
%A Shi, W. J.
%A Liu, Z. K.
%A Chen, F.
%A Chen, Y. L.
%A Rossnagel, K.
%A Bauer, Michael
%T Experimental evidence for a metastable state in FeTe<sub>1−x</sub>Se<sub>x</sub> following coherent-phonon excitation
%J Journal of electron spectroscopy and related phenomena
%V 250
%@ 0368-2048
%C New York, NY [u.a.]
%I Elsevier
%M PUBDB-2021-02576
%P 147085 
%D 2021
%X Changes of the electronic structure of FeTe<sub>1−x</sub>Se<sub>x</sub> (x = 0, 0.3) upon ultrafast excitation with near-infrared laser pulses are investigated using time- and angle-resolved extreme ultraviolet photoemission spectroscopy. At different temperatures and for different doping levels we observe a global oscillation of energy bands near the Fermi energy driven by the coherent excitation of the A<sub>1g</sub>(Te) phonon mode inFeTe<sub>1−x</sub>Se<sub>x</sub>. Prominently, photo-induced band shifts and a spectral weight reduction persist for at least 300 ps, long after the decay of the photo-excited carriers and the damping of the coherent phonons. We argue that the system escapes from the original equilibrium state and is transiently trapped in a possibly metastable state envisioning a purely optical means of manipulating the electronic structure in an iron-based superconductor.  
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000670411800005
%R 10.1016/j.elspec.2021.147085
%U https://bib-pubdb1.desy.de/record/459472