S.-F. Wu, A. Almoalem, I. Feldman, A. Lee, A. Kanigel, G. Blumberg
We study Fe1+yTe0.6Se0.4 multi-band superconductor with Tc = 14K by polarization-resolved Raman spectroscopy. Deep in the superconducting state, we detect pair-breaking excitation at 45cm−1 (2∆ = 5.6 meV) in the XY (B2g) scattering geometry, consistent with twice of the super- conducting gap energy (3meV) revealed by ARPES on the hole-like Fermi pocket with dxz/dyz character. We analyze the superconductivity induced phonon self-energy effects for the B1g(Fe) phonon and estimate the electron-phonon coupling constant λΓ ≈ 0.026, which is insufficient to explain superconductivity with Tc = 14 K.
Phys. Rev. Rev. Research 2,013373
arXiv e-print
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