Linkage between scattering rates and superconductivity in doped ferropnictides

J. Fink; E. D. L. Rienks; M. Yao; R. Kurleto; J. Bannies; S. Aswartham; I. Morozov; S. Wurmehl; T. Wolf; F. Hardy; C. Meingast; H. S. Jeevan; J. Maiwald; P. Gegenwart; C. Felser; B. Buechner

doi:10.1103/physrevb.103.155119

arXiv · 2005.08216

Linkage between scattering rates and superconductivity in doped ferropnictides

J. Fink·E. D. L. Rienks·M. Yao·R. Kurleto·J. Bannies·S. Aswartham·I. Morozov·S. Wurmehl·T. Wolf·F. Hardy·C. Meingast·H. S. Jeevan·J. Maiwald·P. Gegenwart·C. Felser·B. Buechner

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Abstract

We report an angle-resolved photoemission study of a series of hole and electron doped iron-based superconductors, their parent compound BaFe2As2, and their cousins BaCr2As2 and BaCo2As2. We focus on the energy (E) dependent scattering rate Gamma(E) as a function of the 3d count and on the renormalization function Z(E) of the inner hole pocket, which is the hot spot in these compounds. We obtain a non-Fermi-liquid-like linear in energy scattering rate Gamma(E>> kBT), independent of the dopant concentration. The main result is that the slope beta=Gamma(E >> kBT)/E, reaches its maxima near optimal doping and scales with the superconducting transition temperature. This supports the spin fluctuation model for superconductivity for these materials. In the optimally hole-doped compound, the slope of the scattering rate of the inner hole pocket is about three times bigger than the Planckian limit Gamma(E)/E~1. This result together with the energy dependence of the renormalization function Z(E) signals very incoherent charge carriers in the normal state which transform at low temperatures to a coherent unconventional superconducting state.

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J. Fink, E. D. L. Rienks, M. Yao, R. Kurleto, J. Bannies, S. Aswartham, I. Morozov, S. Wurmehl, T. Wolf, F. Hardy, C. Meingast, H. S. Jeevan, J. Maiwald, P. Gegenwart, C. Felser, B. Buechner. 2020-05-17. Linkage between scattering rates and superconductivity in doped ferropnictides. https://doi.org/10.1103/physrevb.103.155119

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