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arXiv · 1409.1537

Anomalous High-Energy Electronic Interaction in Iron-Based Superconductor

D. V. Evtushinsky·A. N. Yaresko·V. B. Zabolotnyy·J. Maletz·T. K. Kim·A. A. Kordyuk·M. S. Viazovska·M. Roslova·I. Morozov·R. Beck·S. Wurmehl·H. Berger·B. Büchner·S. V. Borisenko
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Abstract

Strong electron interactions in solids increase effective mass, and shrink the electronic bands [1]. One of the most unique and robust experimental facts about iron-based superconductors [2-4] is the renormalization of the conduction band by factor of 3 near the Fermi level [5-9]. Obviously related to superconductivity, this unusual behaviour remains unexplained. Here, by studying the momentum-resolved spectrum of the whole valence band in a representative material, we show that this phenomenon originates from electronic interaction on a much larger energy scale. We observe an abrupt depletion of the spectral weight in the middle of the Fe $3d$ band, which is accompanied by a drastic increase of the scattering rate. Remarkably, all spectral anomalies including the low-energy renormalization can be explained by coupling to excitations, strongly peaked at about 0.5 eV. Such high-energy interaction distinguishes all unconventional superconductors from common metals.

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D. V. Evtushinsky, A. N. Yaresko, V. B. Zabolotnyy, J. Maletz, T. K. Kim, A. A. Kordyuk, M. S. Viazovska, M. Roslova, I. Morozov, R. Beck, S. Wurmehl, H. Berger, B. Büchner, S. V. Borisenko. 2014-09-04. Anomalous High-Energy Electronic Interaction in Iron-Based Superconductor. https://doi.org/10.1103/physrevb.96.060501

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