Universal 2Δmax/kBTc scaling decoupled from the electronic coherence in iron-based superconductors

H. Miao; W. H. Brito; Z. P. Yin; R. D. Zhong; G. D. Gu; P. D. Johnson; M. P. M. Dean; S. Choi; G. Kotliar; W. Ku; X. C. Wang; C. Q. Jin; S.-F. Wu; T. Qian; H. Ding

doi:10.1103/PhysRevB.98.020502

Universal 2Δmax/kBTc scaling decoupled from the electronic coherence in iron-based superconductors

H. Miao, W. H. Brito, Z. P. Yin, R. D. Zhong, G. D. Gu, P. D. Johnson, M. P. M. Dean, S. Choi, G. Kotliar, W. Ku, X. C. Wang, C. Q. Jin, S.-F. Wu, T. Qian, H. Ding

DOI 10.1103/PhysRevB.98.020502 · Physical Review B

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Abstract

Here, we use angle-resolved photoemission spectroscopy to study superconductivity that emerges in two extreme cases, from a Fermi-liquid phase (LiFeAs) and an incoherent bad-metal phase (FeTe0.55Se0.45). We find that although the electronic coherence can strongly reshape the single-particle spectral function in the superconducting state, it is decoupled from the maximum-superconducting-gap and Tc ratio 2Δmax/kBTc, which shows a universal scaling that is valid for all iron-based superconductors (FeSCs). Our observation excludes pairing scenarios in the BCS and the BEC limit for FeSCs and calls for a universal strong-coupling pairing mechanism for the FeSCs.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
LiFeAs Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	18	Pressure not reported	unknown
FeTe0.55Se0.45 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	14.5	Pressure not reported	unknown