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Mass Enhancements and Band Shifts in Strongly Hole-Overdoped Fe-Based Pnictide Superconductors: KFe2As2 and CsFe2As2

DOI: 10.1007/s10948-017-4434-5 DOI Help

Authors: S.-l. Drechsler (Leibniz Institute of Solid State Research & Material Science, IFW-Dresden,) , H. Rosner (Max-Planck-Institute for Chemical Physics of Solids,) , V. Grinenko (Leibniz Institute of Solid State Research & Material Science, IFW-Dresden; Institute of Solid State and Materials Physics, TU Dresden) , S. Aswartham (Leibniz Institute of Solid State Research & Material Science, IFW-Dresden,) , I. Morozov (Leibniz Institute of Solid State Research & Material Science, IFW-Dresden; Lomonosov Moscow State University; Lebedev Physical Institute, Russian Academy of Science) , M. Liu (Leibniz Institute of Solid State Research & Material Science, IFW-Dresden; Lomonosov Moscow State University) , A. Boltalin (Lomonosov Moscow State University,) , K. Kihou (National Institute of Advanced Industrial Science & Technology (AIST)) , C. H. Lee (National Institute of Advanced Industrial Science & Technology (AIST)) , T. Kim (Diamond Light Source) , D. Evtushinsky (Institute of Physics, Ecole Polytechnique Federale Lausanne) , J. M. Tomczak (Institute of Solid State Physics, Vienna-University of Technology) , S. Johnston (Tennesee University) , S. Borisenko (Leibniz Institute of Solid State Research & Material Science, IFW-Dresden)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Superconductivity And Novel Magnetism , VOL 254

State: Published (Approved)
Published: January 2018

Abstract: The interplay of high- and low-energy mass renormalizations with band shifts reflected by the positions of van Hove singularities (VHS) in the normal-state spectrum of the most strongly hole-overdoped correlated AFe2As2 (A122) with A=K, Cs is discussed phenomenologically from ARPES data and band-structure (GGA) calculations with full spin-orbit coupling. The big increase of the Sommerfeld coefficient γ from K122 to Cs122 is ascribed to an enhanced coupling to low-energy bosons in the vicinity of a quantum critical point to an unknown, yet incommensurate phase different from the commensurate Mott one. We find no sizeable increase in correlations for Cs122 in contrast to Eilers et al. (Phys. Rev. Lett. 116, 237003 2016). The empirical (ARPES) VHS positions as compared with GGA predictions point even to slightly weaker correlations in Cs122 in accord with low-T magnetic susceptibility χ(T) data and a decreasing Wilson ratio ∝ χ(0)/γ.

Journal Keywords: Pnictides; ARPES; van Hove singularity

Subject Areas: Materials, Physics


Instruments: I05-ARPES