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.
| Original language | English |
|---|---|
| Article number | 020502 |
| Journal | Physical Review B |
| Volume | 98 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jul 9 2018 |
| Externally published | Yes |
Funding
We thank Y. Cao, Y. M. Dai, P. Richard, Y.-L. Wang, and W.-G. Yin for useful discussions. H.M., R.D.Z., M.P.M.D., and P.D.J. were supported by the Center for Emergent Superconductivity, an Energy Frontier Research Center funded by the U.S. DOE, Office of Basic Energy Sciences. W.H.B. was supported by the DOE BES Computational Material Science Program. G.K. was supported by NSF DMR-1733071. Z.P.Y. was supported by the National Natural Science Foundation of China (Grant No. 11674030), the Fundamental Research Funds for the Central Universities (Grant No. 310421113), and the National Key Research and Development Program of China through Contract No. 2016YFA0302300. G.D.G. was supported by the Office of Basic Energy Sciences (BES), U.S. Department of Energy (DOE), through Contract No. de-sc0012704.