Angle-Resolved Photoemission Spectroscopy of Iron-Chalcogenide Superconductor Fe1.03Te0.7Se0.3 : Strong-Coupling Superconductivity and Universality of Inter-Band Scattering

K. Nakayama; T. Sato; P. Richard; T. Kawahara; Y. Sekiba; T. Qian; G. F. Chen; J. L. Luo; N. L. Wang; H. Ding; T. Takahashi

doi:10.1016/j.physc.2011.05.014

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arXiv · 0907.0763

Angle-Resolved Photoemission Spectroscopy of Iron-Chalcogenide Superconductor Fe1.03Te0.7Se0.3 : Strong-Coupling Superconductivity and Universality of Inter-Band Scattering

K. Nakayama·T. Sato·P. Richard·T. Kawahara·Y. Sekiba·T. Qian·G. F. Chen·J. L. Luo·N. L. Wang·H. Ding·T. Takahashi

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Abstract

We have performed high-resolution angle-resolved photoemission spectroscopy of iron-chalcogenide superconductor Fe1.03Te0.7Se0.3 (Tc = 13 K) to investigate the electronic structure relevant to superconductivity. We observed a hole- and an electron-like Fermi surfaces at the Brillouin zone center and corner, respectively, which are nearly nested by the Q~(pi, pi) wave vector. We do not find evidence for the nesting instability with Q~(pi+delta, 0) reminiscent of the antiferromagnetic order in the parent compound Fe1+yTe. We have observed an isotropic superconducting gap along the hole-like Fermi surface with the gap size Delta of ~4 meV (2Delta/kBTc~7), demonstrating the strong-coupling nature of the superconductivity. The observed similarity of low-energy electronic excitations between iron-chalcogenide and iron-arsenide superconductors strongly suggests that common interactions which involve Q~(pi, pi) scattering are responsible for the superconducting pairing.

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K. Nakayama, T. Sato, P. Richard, T. Kawahara, Y. Sekiba, T. Qian, G. F. Chen, J. L. Luo, N. L. Wang, H. Ding, T. Takahashi. 2009-07-04. Angle-Resolved Photoemission Spectroscopy of Iron-Chalcogenide Superconductor Fe1.03Te0.7Se0.3 : Strong-Coupling Superconductivity and Universality of Inter-Band Scattering. https://doi.org/10.1016/j.physc.2011.05.014

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